diff --git a/src/PhpSpreadsheet/Calculation/Calculation.php b/src/PhpSpreadsheet/Calculation/Calculation.php
index a3f45f19..bc0baa4d 100644
--- a/src/PhpSpreadsheet/Calculation/Calculation.php
+++ b/src/PhpSpreadsheet/Calculation/Calculation.php
@@ -328,17 +328,17 @@ class Calculation
         ],
         'AVEDEV' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'AVEDEV'],
+            'functionCall' => [Statistical\Averages::class, 'AVEDEV'],
             'argumentCount' => '1+',
         ],
         'AVERAGE' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'AVERAGE'],
+            'functionCall' => [Statistical\Averages::class, 'AVERAGE'],
             'argumentCount' => '1+',
         ],
         'AVERAGEA' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'AVERAGEA'],
+            'functionCall' => [Statistical\Averages::class, 'AVERAGEA'],
             'argumentCount' => '1+',
         ],
         'AVERAGEIF' => [
@@ -624,17 +624,17 @@ class Calculation
         ],
         'COUNT' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'COUNT'],
+            'functionCall' => [Statistical\Counts::class, 'COUNT'],
             'argumentCount' => '1+',
         ],
         'COUNTA' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'COUNTA'],
+            'functionCall' => [Statistical\Counts::class, 'COUNTA'],
             'argumentCount' => '1+',
         ],
         'COUNTBLANK' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'COUNTBLANK'],
+            'functionCall' => [Statistical\Counts::class, 'COUNTBLANK'],
             'argumentCount' => '1',
         ],
         'COUNTIF' => [
@@ -1620,12 +1620,12 @@ class Calculation
         ],
         'MAX' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'MAX'],
+            'functionCall' => [Statistical\Maximum::class, 'MAX'],
             'argumentCount' => '1+',
         ],
         'MAXA' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'MAXA'],
+            'functionCall' => [Statistical\Maximum::class, 'MAXA'],
             'argumentCount' => '1+',
         ],
         'MAXIFS' => [
@@ -1665,12 +1665,12 @@ class Calculation
         ],
         'MIN' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'MIN'],
+            'functionCall' => [Statistical\Minimum::class, 'MIN'],
             'argumentCount' => '1+',
         ],
         'MINA' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'MINA'],
+            'functionCall' => [Statistical\Minimum::class, 'MINA'],
             'argumentCount' => '1+',
         ],
         'MINIFS' => [
@@ -2263,22 +2263,22 @@ class Calculation
         ],
         'STDEV' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'STDEV'],
+            'functionCall' => [Statistical\StandardDeviations::class, 'STDEV'],
             'argumentCount' => '1+',
         ],
         'STDEV.S' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'STDEV'],
+            'functionCall' => [Statistical\StandardDeviations::class, 'STDEV'],
             'argumentCount' => '1+',
         ],
         'STDEV.P' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'STDEVP'],
+            'functionCall' => [Statistical\StandardDeviations::class, 'STDEVP'],
             'argumentCount' => '1+',
         ],
         'STDEVA' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'STDEVA'],
+            'functionCall' => [Statistical\StandardDeviations::class, 'STDEVA'],
             'argumentCount' => '1+',
         ],
         'STDEVP' => [
@@ -2524,32 +2524,32 @@ class Calculation
         ],
         'VAR' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'VARFunc'],
+            'functionCall' => [Statistical\Variances::class, 'VAR'],
             'argumentCount' => '1+',
         ],
         'VAR.P' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'VARP'],
+            'functionCall' => [Statistical\Variances::class, 'VARP'],
             'argumentCount' => '1+',
         ],
         'VAR.S' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'VARFunc'],
+            'functionCall' => [Statistical\Variances::class, 'VAR'],
             'argumentCount' => '1+',
         ],
         'VARA' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'VARA'],
+            'functionCall' => [Statistical\Variances::class, 'VARA'],
             'argumentCount' => '1+',
         ],
         'VARP' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'VARP'],
+            'functionCall' => [Statistical\Variances::class, 'VARP'],
             'argumentCount' => '1+',
         ],
         'VARPA' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'VARPA'],
+            'functionCall' => [Statistical\Variances::class, 'VARPA'],
             'argumentCount' => '1+',
         ],
         'VDB' => [
diff --git a/src/PhpSpreadsheet/Calculation/Database/DAverage.php b/src/PhpSpreadsheet/Calculation/Database/DAverage.php
index ea45beda..738cb78e 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DAverage.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DAverage.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Averages;
 
 class DAverage extends DatabaseAbstract
 {
@@ -38,7 +38,7 @@ class DAverage extends DatabaseAbstract
             return null;
         }
 
-        return Statistical::AVERAGE(
+        return Averages::AVERAGE(
             self::getFilteredColumn($database, $field, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DCount.php b/src/PhpSpreadsheet/Calculation/Database/DCount.php
index da173c8c..bf41d6b5 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DCount.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DCount.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Counts;
 
 class DCount extends DatabaseAbstract
 {
@@ -36,7 +36,7 @@ class DCount extends DatabaseAbstract
     {
         $field = self::fieldExtract($database, $field);
 
-        return Statistical::COUNT(
+        return Counts::COUNT(
             self::getFilteredColumn($database, $field, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DCountA.php b/src/PhpSpreadsheet/Calculation/Database/DCountA.php
index 1beaf012..c48e53c5 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DCountA.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DCountA.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Counts;
 
 class DCountA extends DatabaseAbstract
 {
@@ -35,7 +35,7 @@ class DCountA extends DatabaseAbstract
     {
         $field = self::fieldExtract($database, $field);
 
-        return Statistical::COUNTA(
+        return Counts::COUNTA(
             self::getFilteredColumn($database, $field ?? 0, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DMax.php b/src/PhpSpreadsheet/Calculation/Database/DMax.php
index 8918c54d..6cf2f20d 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DMax.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DMax.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Maximum;
 
 class DMax extends DatabaseAbstract
 {
@@ -39,7 +39,7 @@ class DMax extends DatabaseAbstract
             return null;
         }
 
-        return Statistical::MAX(
+        return Maximum::MAX(
             self::getFilteredColumn($database, $field, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DMin.php b/src/PhpSpreadsheet/Calculation/Database/DMin.php
index 357c9a91..5668bcf6 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DMin.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DMin.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Minimum;
 
 class DMin extends DatabaseAbstract
 {
@@ -39,7 +39,7 @@ class DMin extends DatabaseAbstract
             return null;
         }
 
-        return Statistical::MIN(
+        return Minimum::MIN(
             self::getFilteredColumn($database, $field, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DStDev.php b/src/PhpSpreadsheet/Calculation/Database/DStDev.php
index 58bb4f7d..cfc7e952 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DStDev.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DStDev.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\StandardDeviations;
 
 class DStDev extends DatabaseAbstract
 {
@@ -39,7 +39,7 @@ class DStDev extends DatabaseAbstract
             return null;
         }
 
-        return Statistical::STDEV(
+        return StandardDeviations::STDEV(
             self::getFilteredColumn($database, $field, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DStDevP.php b/src/PhpSpreadsheet/Calculation/Database/DStDevP.php
index 0d2e050d..2a04c5d9 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DStDevP.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DStDevP.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\StandardDeviations;
 
 class DStDevP extends DatabaseAbstract
 {
@@ -39,7 +39,7 @@ class DStDevP extends DatabaseAbstract
             return null;
         }
 
-        return Statistical::STDEVP(
+        return StandardDeviations::STDEVP(
             self::getFilteredColumn($database, $field, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DVar.php b/src/PhpSpreadsheet/Calculation/Database/DVar.php
index 62c9f6c6..c70da073 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DVar.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DVar.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Variances;
 
 class DVar extends DatabaseAbstract
 {
@@ -39,7 +39,7 @@ class DVar extends DatabaseAbstract
             return null;
         }
 
-        return Statistical::VARFunc(
+        return Variances::VAR(
             self::getFilteredColumn($database, $field, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DVarP.php b/src/PhpSpreadsheet/Calculation/Database/DVarP.php
index 3a9744cb..f22f2cca 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DVarP.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DVarP.php
@@ -2,7 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Database;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Variances;
 
 class DVarP extends DatabaseAbstract
 {
@@ -39,7 +39,7 @@ class DVarP extends DatabaseAbstract
             return null;
         }
 
-        return Statistical::VARP(
+        return Variances::VARP(
             self::getFilteredColumn($database, $field, $criteria)
         );
     }
diff --git a/src/PhpSpreadsheet/Calculation/MathTrig.php b/src/PhpSpreadsheet/Calculation/MathTrig.php
index 5a966cbf..e72e24cd 100644
--- a/src/PhpSpreadsheet/Calculation/MathTrig.php
+++ b/src/PhpSpreadsheet/Calculation/MathTrig.php
@@ -1222,27 +1222,27 @@ class MathTrig
             $aArgs = self::filterFormulaArgs($cellReference, $aArgs);
             switch ($subtotal) {
                 case 1:
-                    return Statistical::AVERAGE($aArgs);
+                    return Statistical\Averages::AVERAGE($aArgs);
                 case 2:
-                    return Statistical::COUNT($aArgs);
+                    return Statistical\Counts::COUNT($aArgs);
                 case 3:
-                    return Statistical::COUNTA($aArgs);
+                    return Statistical\Counts::COUNTA($aArgs);
                 case 4:
-                    return Statistical::MAX($aArgs);
+                    return Statistical\Maximum::MAX($aArgs);
                 case 5:
-                    return Statistical::MIN($aArgs);
+                    return Statistical\Minimum::MIN($aArgs);
                 case 6:
                     return self::PRODUCT($aArgs);
                 case 7:
-                    return Statistical::STDEV($aArgs);
+                    return Statistical\StandardDeviations::STDEV($aArgs);
                 case 8:
-                    return Statistical::STDEVP($aArgs);
+                    return Statistical\StandardDeviations::STDEVP($aArgs);
                 case 9:
                     return self::SUM($aArgs);
                 case 10:
-                    return Statistical::VARFunc($aArgs);
+                    return Statistical\Variances::VAR($aArgs);
                 case 11:
-                    return Statistical::VARP($aArgs);
+                    return Statistical\Variances::VARP($aArgs);
             }
         }
 
diff --git a/src/PhpSpreadsheet/Calculation/Statistical.php b/src/PhpSpreadsheet/Calculation/Statistical.php
index 2f695d5b..dc9c5b44 100644
--- a/src/PhpSpreadsheet/Calculation/Statistical.php
+++ b/src/PhpSpreadsheet/Calculation/Statistical.php
@@ -2,8 +2,14 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Averages;
 use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Conditional;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Counts;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Maximum;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Minimum;
 use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Permutations;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\StandardDeviations;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Variances;
 use PhpOffice\PhpSpreadsheet\Shared\Trend\Trend;
 
 class Statistical
@@ -520,48 +526,6 @@ class Statistical
         return Functions::NULL();
     }
 
-    /**
-     * MS Excel does not count Booleans if passed as cell values, but they are counted if passed as literals.
-     * OpenOffice Calc always counts Booleans.
-     * Gnumeric never counts Booleans.
-     *
-     * @param mixed $arg
-     * @param mixed $k
-     *
-     * @return int|mixed
-     */
-    private static function testAcceptedBoolean($arg, $k)
-    {
-        if (
-            (is_bool($arg)) &&
-            ((!Functions::isCellValue($k) && (Functions::getCompatibilityMode() === Functions::COMPATIBILITY_EXCEL)) ||
-                (Functions::getCompatibilityMode() === Functions::COMPATIBILITY_OPENOFFICE))
-        ) {
-            $arg = (int) $arg;
-        }
-
-        return $arg;
-    }
-
-    /**
-     * @param mixed $arg
-     * @param mixed $k
-     *
-     * @return bool
-     */
-    private static function isAcceptedCountable($arg, $k)
-    {
-        if (
-            ((is_numeric($arg)) && (!is_string($arg))) ||
-                ((is_numeric($arg)) && (!Functions::isCellValue($k)) &&
-                    (Functions::getCompatibilityMode() !== Functions::COMPATIBILITY_GNUMERIC))
-        ) {
-            return true;
-        }
-
-        return false;
-    }
-
     /**
      * AVEDEV.
      *
@@ -571,45 +535,18 @@ class Statistical
      * Excel Function:
      *        AVEDEV(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Averages::AVEDEV()
+     *      Use the AVEDEV() method in the Statistical\Averages class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string
      */
     public static function AVEDEV(...$args)
     {
-        $aArgs = Functions::flattenArrayIndexed($args);
-
-        // Return value
-        $returnValue = 0;
-
-        $aMean = self::AVERAGE(...$args);
-        if ($aMean === Functions::DIV0()) {
-            return Functions::NAN();
-        } elseif ($aMean === Functions::VALUE()) {
-            return Functions::VALUE();
-        }
-
-        $aCount = 0;
-        foreach ($aArgs as $k => $arg) {
-            $arg = self::testAcceptedBoolean($arg, $k);
-            // Is it a numeric value?
-            // Strings containing numeric values are only counted if they are string literals (not cell values)
-            //    and then only in MS Excel and in Open Office, not in Gnumeric
-            if ((is_string($arg)) && (!is_numeric($arg)) && (!Functions::isCellValue($k))) {
-                return Functions::VALUE();
-            }
-            if (self::isAcceptedCountable($arg, $k)) {
-                $returnValue += abs($arg - $aMean);
-                ++$aCount;
-            }
-        }
-
-        // Return
-        if ($aCount === 0) {
-            return Functions::DIV0();
-        }
-
-        return $returnValue / $aCount;
+        return Averages::AVEDEV(...$args);
     }
 
     /**
@@ -620,35 +557,18 @@ class Statistical
      * Excel Function:
      *        AVERAGE(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Averages::AVERAGE()
+     *      Use the AVERAGE() method in the Statistical\Averages class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string
      */
     public static function AVERAGE(...$args)
     {
-        $returnValue = $aCount = 0;
-
-        // Loop through arguments
-        foreach (Functions::flattenArrayIndexed($args) as $k => $arg) {
-            $arg = self::testAcceptedBoolean($arg, $k);
-            // Is it a numeric value?
-            // Strings containing numeric values are only counted if they are string literals (not cell values)
-            //    and then only in MS Excel and in Open Office, not in Gnumeric
-            if ((is_string($arg)) && (!is_numeric($arg)) && (!Functions::isCellValue($k))) {
-                return Functions::VALUE();
-            }
-            if (self::isAcceptedCountable($arg, $k)) {
-                $returnValue += $arg;
-                ++$aCount;
-            }
-        }
-
-        // Return
-        if ($aCount > 0) {
-            return $returnValue / $aCount;
-        }
-
-        return Functions::DIV0();
+        return Averages::AVERAGE(...$args);
     }
 
     /**
@@ -659,39 +579,18 @@ class Statistical
      * Excel Function:
      *        AVERAGEA(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Averages::AVERAGEA()
+     *      Use the AVERAGEA() method in the Statistical\Averages class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string
      */
     public static function AVERAGEA(...$args)
     {
-        $returnValue = null;
-
-        $aCount = 0;
-        // Loop through arguments
-        foreach (Functions::flattenArrayIndexed($args) as $k => $arg) {
-            if (
-                (is_bool($arg)) &&
-                (!Functions::isMatrixValue($k))
-            ) {
-            } else {
-                if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
-                    if (is_bool($arg)) {
-                        $arg = (int) $arg;
-                    } elseif (is_string($arg)) {
-                        $arg = 0;
-                    }
-                    $returnValue += $arg;
-                    ++$aCount;
-                }
-            }
-        }
-
-        if ($aCount > 0) {
-            return $returnValue / $aCount;
-        }
-
-        return Functions::DIV0();
+        return Averages::AVERAGEA(...$args);
     }
 
     /**
@@ -715,7 +614,7 @@ class Statistical
      */
     public static function AVERAGEIF($range, $condition, $averageRange = [])
     {
-        return Statistical\Conditional::AVERAGEIF($range, $condition, $averageRange);
+        return Conditional::AVERAGEIF($range, $condition, $averageRange);
     }
 
     /**
@@ -1026,27 +925,18 @@ class Statistical
      * Excel Function:
      *        COUNT(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Counts::COUNT()
+     *      Use the COUNT() method in the Statistical\Counts class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return int
      */
     public static function COUNT(...$args)
     {
-        $returnValue = 0;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArrayIndexed($args);
-        foreach ($aArgs as $k => $arg) {
-            $arg = self::testAcceptedBoolean($arg, $k);
-            // Is it a numeric value?
-            // Strings containing numeric values are only counted if they are string literals (not cell values)
-            //    and then only in MS Excel and in Open Office, not in Gnumeric
-            if (self::isAcceptedCountable($arg, $k)) {
-                ++$returnValue;
-            }
-        }
-
-        return $returnValue;
+        return Counts::COUNT(...$args);
     }
 
     /**
@@ -1057,24 +947,18 @@ class Statistical
      * Excel Function:
      *        COUNTA(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Counts::COUNTA()
+     *      Use the COUNTA() method in the Statistical\Counts class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return int
      */
     public static function COUNTA(...$args)
     {
-        $returnValue = 0;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArrayIndexed($args);
-        foreach ($aArgs as $k => $arg) {
-            // Nulls are counted if literals, but not if cell values
-            if ($arg !== null || (!Functions::isCellValue($k))) {
-                ++$returnValue;
-            }
-        }
-
-        return $returnValue;
+        return Counts::COUNTA(...$args);
     }
 
     /**
@@ -1085,24 +969,18 @@ class Statistical
      * Excel Function:
      *        COUNTBLANK(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Counts::COUNTBLANK()
+     *      Use the COUNTBLANK() method in the Statistical\Counts class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return int
      */
     public static function COUNTBLANK(...$args)
     {
-        $returnValue = 0;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArray($args);
-        foreach ($aArgs as $arg) {
-            // Is it a blank cell?
-            if (($arg === null) || ((is_string($arg)) && ($arg == ''))) {
-                ++$returnValue;
-            }
-        }
-
-        return $returnValue;
+        return Counts::COUNTBLANK(...$args);
     }
 
     /**
@@ -1125,7 +1003,7 @@ class Statistical
      */
     public static function COUNTIF($range, $condition)
     {
-        return Statistical\Conditional::COUNTIF($range, $condition);
+        return Conditional::COUNTIF($range, $condition);
     }
 
     /**
@@ -1147,7 +1025,7 @@ class Statistical
      */
     public static function COUNTIFS(...$args)
     {
-        return Statistical\Conditional::COUNTIFS(...$args);
+        return Conditional::COUNTIFS(...$args);
     }
 
     /**
@@ -1325,7 +1203,7 @@ class Statistical
         // Return value
         $returnValue = null;
 
-        $aMean = self::AVERAGE($aArgs);
+        $aMean = Averages::AVERAGE($aArgs);
         if ($aMean != Functions::DIV0()) {
             $aCount = -1;
             foreach ($aArgs as $k => $arg) {
@@ -1711,8 +1589,8 @@ class Statistical
 
         $aMean = MathTrig::PRODUCT($aArgs);
         if (is_numeric($aMean) && ($aMean > 0)) {
-            $aCount = self::COUNT($aArgs);
-            if (self::MIN($aArgs) > 0) {
+            $aCount = Counts::COUNT($aArgs);
+            if (Minimum::MIN($aArgs) > 0) {
                 return $aMean ** (1 / $aCount);
             }
         }
@@ -1772,7 +1650,7 @@ class Statistical
 
         // Loop through arguments
         $aArgs = Functions::flattenArray($args);
-        if (self::MIN($aArgs) < 0) {
+        if (Minimum::MIN($aArgs) < 0) {
             return Functions::NAN();
         }
         $aCount = 0;
@@ -1883,8 +1761,8 @@ class Statistical
     public static function KURT(...$args)
     {
         $aArgs = Functions::flattenArrayIndexed($args);
-        $mean = self::AVERAGE($aArgs);
-        $stdDev = self::STDEV($aArgs);
+        $mean = Averages::AVERAGE($aArgs);
+        $stdDev = StandardDeviations::STDEV($aArgs);
 
         if ($stdDev > 0) {
             $count = $summer = 0;
@@ -1941,7 +1819,7 @@ class Statistical
                     $mArgs[] = $arg;
                 }
             }
-            $count = self::COUNT($mArgs);
+            $count = Counts::COUNT($mArgs);
             --$entry;
             if (($entry < 0) || ($entry >= $count) || ($count == 0)) {
                 return Functions::NAN();
@@ -2184,30 +2062,18 @@ class Statistical
      * Excel Function:
      *        MAX(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Maximum::MAX()
+     *      Use the MAX() method in the Statistical\Maximum class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float
      */
     public static function MAX(...$args)
     {
-        $returnValue = null;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArray($args);
-        foreach ($aArgs as $arg) {
-            // Is it a numeric value?
-            if ((is_numeric($arg)) && (!is_string($arg))) {
-                if (($returnValue === null) || ($arg > $returnValue)) {
-                    $returnValue = $arg;
-                }
-            }
-        }
-
-        if ($returnValue === null) {
-            return 0;
-        }
-
-        return $returnValue;
+        return Maximum::MAX(...$args);
     }
 
     /**
@@ -2218,35 +2084,18 @@ class Statistical
      * Excel Function:
      *        MAXA(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Maximum::MAXA()
+     *      Use the MAXA() method in the Statistical\Maximum class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float
      */
     public static function MAXA(...$args)
     {
-        $returnValue = null;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArray($args);
-        foreach ($aArgs as $arg) {
-            // Is it a numeric value?
-            if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
-                if (is_bool($arg)) {
-                    $arg = (int) $arg;
-                } elseif (is_string($arg)) {
-                    $arg = 0;
-                }
-                if (($returnValue === null) || ($arg > $returnValue)) {
-                    $returnValue = $arg;
-                }
-            }
-        }
-
-        if ($returnValue === null) {
-            return 0;
-        }
-
-        return $returnValue;
+        return Maximum::MAXA(...$args);
     }
 
     /**
@@ -2321,30 +2170,18 @@ class Statistical
      * Excel Function:
      *        MIN(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Minimum::MIN()
+     *      Use the MIN() method in the Statistical\Minimum class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float
      */
     public static function MIN(...$args)
     {
-        $returnValue = null;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArray($args);
-        foreach ($aArgs as $arg) {
-            // Is it a numeric value?
-            if ((is_numeric($arg)) && (!is_string($arg))) {
-                if (($returnValue === null) || ($arg < $returnValue)) {
-                    $returnValue = $arg;
-                }
-            }
-        }
-
-        if ($returnValue === null) {
-            return 0;
-        }
-
-        return $returnValue;
+        return Minimum::MIN(...$args);
     }
 
     /**
@@ -2355,35 +2192,18 @@ class Statistical
      * Excel Function:
      *        MINA(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Minimum::MINA()
+     *      Use the MINA() method in the Statistical\Minimum class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float
      */
     public static function MINA(...$args)
     {
-        $returnValue = null;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArray($args);
-        foreach ($aArgs as $arg) {
-            // Is it a numeric value?
-            if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
-                if (is_bool($arg)) {
-                    $arg = (int) $arg;
-                } elseif (is_string($arg)) {
-                    $arg = 0;
-                }
-                if (($returnValue === null) || ($arg < $returnValue)) {
-                    $returnValue = $arg;
-                }
-            }
-        }
-
-        if ($returnValue === null) {
-            return 0;
-        }
-
-        return $returnValue;
+        return Minimum::MINA(...$args);
     }
 
     /**
@@ -2688,7 +2508,7 @@ class Statistical
             $mValueCount = count($mArgs);
             if ($mValueCount > 0) {
                 sort($mArgs);
-                $count = self::COUNT($mArgs);
+                $count = Counts::COUNT($mArgs);
                 $index = $entry * ($count - 1);
                 $iBase = floor($index);
                 if ($index == $iBase) {
@@ -2775,7 +2595,7 @@ class Statistical
      */
     public static function PERMUT($numObjs, $numInSet)
     {
-        return Statistical\Permutations::PERMUT($numObjs, $numInSet);
+        return Permutations::PERMUT($numObjs, $numInSet);
     }
 
     /**
@@ -2930,8 +2750,8 @@ class Statistical
     public static function SKEW(...$args)
     {
         $aArgs = Functions::flattenArrayIndexed($args);
-        $mean = self::AVERAGE($aArgs);
-        $stdDev = self::STDEV($aArgs);
+        $mean = Averages::AVERAGE($aArgs);
+        $stdDev = StandardDeviations::STDEV($aArgs);
 
         $count = $summer = 0;
         // Loop through arguments
@@ -3015,7 +2835,7 @@ class Statistical
                     $mArgs[] = $arg;
                 }
             }
-            $count = self::COUNT($mArgs);
+            $count = Counts::COUNT($mArgs);
             --$entry;
             if (($entry < 0) || ($entry >= $count) || ($count == 0)) {
                 return Functions::NAN();
@@ -3065,45 +2885,18 @@ class Statistical
      * Excel Function:
      *        STDEV(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\StandardDeviations::STDEV()
+     *      Use the STDEV() method in the Statistical\StandardDeviations class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string The result, or a string containing an error
      */
     public static function STDEV(...$args)
     {
-        $aArgs = Functions::flattenArrayIndexed($args);
-
-        // Return value
-        $returnValue = null;
-
-        $aMean = self::AVERAGE($aArgs);
-        if ($aMean !== null) {
-            $aCount = -1;
-            foreach ($aArgs as $k => $arg) {
-                if (
-                    (is_bool($arg)) &&
-                    ((!Functions::isCellValue($k)) || (Functions::getCompatibilityMode() == Functions::COMPATIBILITY_OPENOFFICE))
-                ) {
-                    $arg = (int) $arg;
-                }
-                // Is it a numeric value?
-                if ((is_numeric($arg)) && (!is_string($arg))) {
-                    if ($returnValue === null) {
-                        $returnValue = ($arg - $aMean) ** 2;
-                    } else {
-                        $returnValue += ($arg - $aMean) ** 2;
-                    }
-                    ++$aCount;
-                }
-            }
-
-            // Return
-            if (($aCount > 0) && ($returnValue >= 0)) {
-                return sqrt($returnValue / $aCount);
-            }
-        }
-
-        return Functions::DIV0();
+        return StandardDeviations::STDEV(...$args);
     }
 
     /**
@@ -3114,48 +2907,18 @@ class Statistical
      * Excel Function:
      *        STDEVA(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\StandardDeviations::STDEVA()
+     *      Use the STDEVA() method in the Statistical\StandardDeviations class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string
      */
     public static function STDEVA(...$args)
     {
-        $aArgs = Functions::flattenArrayIndexed($args);
-
-        $returnValue = null;
-
-        $aMean = self::AVERAGEA($aArgs);
-        if ($aMean !== null) {
-            $aCount = -1;
-            foreach ($aArgs as $k => $arg) {
-                if (
-                    (is_bool($arg)) &&
-                    (!Functions::isMatrixValue($k))
-                ) {
-                } else {
-                    // Is it a numeric value?
-                    if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) & ($arg != '')))) {
-                        if (is_bool($arg)) {
-                            $arg = (int) $arg;
-                        } elseif (is_string($arg)) {
-                            $arg = 0;
-                        }
-                        if ($returnValue === null) {
-                            $returnValue = ($arg - $aMean) ** 2;
-                        } else {
-                            $returnValue += ($arg - $aMean) ** 2;
-                        }
-                        ++$aCount;
-                    }
-                }
-            }
-
-            if (($aCount > 0) && ($returnValue >= 0)) {
-                return sqrt($returnValue / $aCount);
-            }
-        }
-
-        return Functions::DIV0();
+        return StandardDeviations::STDEVA(...$args);
     }
 
     /**
@@ -3166,43 +2929,18 @@ class Statistical
      * Excel Function:
      *        STDEVP(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\StandardDeviations::STDEVP()
+     *      Use the STDEVP() method in the Statistical\StandardDeviations class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string
      */
     public static function STDEVP(...$args)
     {
-        $aArgs = Functions::flattenArrayIndexed($args);
-
-        $returnValue = null;
-
-        $aMean = self::AVERAGE($aArgs);
-        if ($aMean !== null) {
-            $aCount = 0;
-            foreach ($aArgs as $k => $arg) {
-                if (
-                    (is_bool($arg)) &&
-                    ((!Functions::isCellValue($k)) || (Functions::getCompatibilityMode() == Functions::COMPATIBILITY_OPENOFFICE))
-                ) {
-                    $arg = (int) $arg;
-                }
-                // Is it a numeric value?
-                if ((is_numeric($arg)) && (!is_string($arg))) {
-                    if ($returnValue === null) {
-                        $returnValue = ($arg - $aMean) ** 2;
-                    } else {
-                        $returnValue += ($arg - $aMean) ** 2;
-                    }
-                    ++$aCount;
-                }
-            }
-
-            if (($aCount > 0) && ($returnValue >= 0)) {
-                return sqrt($returnValue / $aCount);
-            }
-        }
-
-        return Functions::DIV0();
+        return StandardDeviations::STDEVP(...$args);
     }
 
     /**
@@ -3213,48 +2951,18 @@ class Statistical
      * Excel Function:
      *        STDEVPA(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\StandardDeviations::STDEVPA()
+     *      Use the STDEVPA() method in the Statistical\StandardDeviations class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string
      */
     public static function STDEVPA(...$args)
     {
-        $aArgs = Functions::flattenArrayIndexed($args);
-
-        $returnValue = null;
-
-        $aMean = self::AVERAGEA($aArgs);
-        if ($aMean !== null) {
-            $aCount = 0;
-            foreach ($aArgs as $k => $arg) {
-                if (
-                    (is_bool($arg)) &&
-                    (!Functions::isMatrixValue($k))
-                ) {
-                } else {
-                    // Is it a numeric value?
-                    if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) & ($arg != '')))) {
-                        if (is_bool($arg)) {
-                            $arg = (int) $arg;
-                        } elseif (is_string($arg)) {
-                            $arg = 0;
-                        }
-                        if ($returnValue === null) {
-                            $returnValue = ($arg - $aMean) ** 2;
-                        } else {
-                            $returnValue += ($arg - $aMean) ** 2;
-                        }
-                        ++$aCount;
-                    }
-                }
-            }
-
-            if (($aCount > 0) && ($returnValue >= 0)) {
-                return sqrt($returnValue / $aCount);
-            }
-        }
-
-        return Functions::DIV0();
+        return StandardDeviations::STDEVPA(...$args);
     }
 
     /**
@@ -3472,14 +3180,14 @@ class Statistical
                     $mArgs[] = $arg;
                 }
             }
-            $discard = floor(self::COUNT($mArgs) * $percent / 2);
+            $discard = floor(Counts::COUNT($mArgs) * $percent / 2);
             sort($mArgs);
             for ($i = 0; $i < $discard; ++$i) {
                 array_pop($mArgs);
                 array_shift($mArgs);
             }
 
-            return self::AVERAGE($mArgs);
+            return Averages::AVERAGE($mArgs);
         }
 
         return Functions::VALUE();
@@ -3493,38 +3201,18 @@ class Statistical
      * Excel Function:
      *        VAR(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string (string if result is an error)
+     *
+     *@see Statistical\Variances::VAR()
+     *      Use the VAR() method in the Statistical\Variances class instead
      */
     public static function VARFunc(...$args)
     {
-        $returnValue = Functions::DIV0();
-
-        $summerA = $summerB = 0;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArray($args);
-        $aCount = 0;
-        foreach ($aArgs as $arg) {
-            if (is_bool($arg)) {
-                $arg = (int) $arg;
-            }
-            // Is it a numeric value?
-            if ((is_numeric($arg)) && (!is_string($arg))) {
-                $summerA += ($arg * $arg);
-                $summerB += $arg;
-                ++$aCount;
-            }
-        }
-
-        if ($aCount > 1) {
-            $summerA *= $aCount;
-            $summerB *= $summerB;
-            $returnValue = ($summerA - $summerB) / ($aCount * ($aCount - 1));
-        }
-
-        return $returnValue;
+        return Variances::VAR(...$args);
     }
 
     /**
@@ -3535,51 +3223,18 @@ class Statistical
      * Excel Function:
      *        VARA(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Variances::VARA()
+     *      Use the VARA() method in the Statistical\Variances class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string (string if result is an error)
      */
     public static function VARA(...$args)
     {
-        $returnValue = Functions::DIV0();
-
-        $summerA = $summerB = 0;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArrayIndexed($args);
-        $aCount = 0;
-        foreach ($aArgs as $k => $arg) {
-            if (
-                (is_string($arg)) &&
-                (Functions::isValue($k))
-            ) {
-                return Functions::VALUE();
-            } elseif (
-                (is_string($arg)) &&
-                (!Functions::isMatrixValue($k))
-            ) {
-            } else {
-                // Is it a numeric value?
-                if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) & ($arg != '')))) {
-                    if (is_bool($arg)) {
-                        $arg = (int) $arg;
-                    } elseif (is_string($arg)) {
-                        $arg = 0;
-                    }
-                    $summerA += ($arg * $arg);
-                    $summerB += $arg;
-                    ++$aCount;
-                }
-            }
-        }
-
-        if ($aCount > 1) {
-            $summerA *= $aCount;
-            $summerB *= $summerB;
-            $returnValue = ($summerA - $summerB) / ($aCount * ($aCount - 1));
-        }
-
-        return $returnValue;
+        return Variances::VARA(...$args);
     }
 
     /**
@@ -3590,39 +3245,18 @@ class Statistical
      * Excel Function:
      *        VARP(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Variances::VARP()
+     *      Use the VARP() method in the Statistical\Variances class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string (string if result is an error)
      */
     public static function VARP(...$args)
     {
-        // Return value
-        $returnValue = Functions::DIV0();
-
-        $summerA = $summerB = 0;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArray($args);
-        $aCount = 0;
-        foreach ($aArgs as $arg) {
-            if (is_bool($arg)) {
-                $arg = (int) $arg;
-            }
-            // Is it a numeric value?
-            if ((is_numeric($arg)) && (!is_string($arg))) {
-                $summerA += ($arg * $arg);
-                $summerB += $arg;
-                ++$aCount;
-            }
-        }
-
-        if ($aCount > 0) {
-            $summerA *= $aCount;
-            $summerB *= $summerB;
-            $returnValue = ($summerA - $summerB) / ($aCount * $aCount);
-        }
-
-        return $returnValue;
+        return Variances::VARP(...$args);
     }
 
     /**
@@ -3633,51 +3267,18 @@ class Statistical
      * Excel Function:
      *        VARPA(value1[,value2[, ...]])
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Variances::VARPA()
+     *      Use the VARPA() method in the Statistical\Variances class instead
+     *
      * @param mixed ...$args Data values
      *
      * @return float|string (string if result is an error)
      */
     public static function VARPA(...$args)
     {
-        $returnValue = Functions::DIV0();
-
-        $summerA = $summerB = 0;
-
-        // Loop through arguments
-        $aArgs = Functions::flattenArrayIndexed($args);
-        $aCount = 0;
-        foreach ($aArgs as $k => $arg) {
-            if (
-                (is_string($arg)) &&
-                (Functions::isValue($k))
-            ) {
-                return Functions::VALUE();
-            } elseif (
-                (is_string($arg)) &&
-                (!Functions::isMatrixValue($k))
-            ) {
-            } else {
-                // Is it a numeric value?
-                if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) & ($arg != '')))) {
-                    if (is_bool($arg)) {
-                        $arg = (int) $arg;
-                    } elseif (is_string($arg)) {
-                        $arg = 0;
-                    }
-                    $summerA += ($arg * $arg);
-                    $summerB += $arg;
-                    ++$aCount;
-                }
-            }
-        }
-
-        if ($aCount > 0) {
-            $summerA *= $aCount;
-            $summerB *= $summerB;
-            $returnValue = ($summerA - $summerB) / ($aCount * $aCount);
-        }
-
-        return $returnValue;
+        return Variances::VARPA(...$args);
     }
 
     /**
@@ -3734,10 +3335,10 @@ class Statistical
         $sigma = Functions::flattenSingleValue($sigma);
 
         if ($sigma === null) {
-            $sigma = self::STDEV($dataSet);
+            $sigma = StandardDeviations::STDEV($dataSet);
         }
         $n = count($dataSet);
 
-        return 1 - self::NORMSDIST((self::AVERAGE($dataSet) - $m0) / ($sigma / sqrt($n)));
+        return 1 - self::NORMSDIST((Averages::AVERAGE($dataSet) - $m0) / ($sigma / sqrt($n)));
     }
 }
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/AggregateBase.php b/src/PhpSpreadsheet/Calculation/Statistical/AggregateBase.php
new file mode 100644
index 00000000..75c012dc
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/AggregateBase.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+abstract class AggregateBase
+{
+    /**
+     * MS Excel does not count Booleans if passed as cell values, but they are counted if passed as literals.
+     * OpenOffice Calc always counts Booleans.
+     * Gnumeric never counts Booleans.
+     *
+     * @param mixed $arg
+     * @param mixed $k
+     *
+     * @return int|mixed
+     */
+    protected static function testAcceptedBoolean($arg, $k)
+    {
+        if (
+            (is_bool($arg)) &&
+            ((!Functions::isCellValue($k) && (Functions::getCompatibilityMode() === Functions::COMPATIBILITY_EXCEL)) ||
+                (Functions::getCompatibilityMode() === Functions::COMPATIBILITY_OPENOFFICE))
+        ) {
+            $arg = (int) $arg;
+        }
+
+        return $arg;
+    }
+
+    /**
+     * @param mixed $arg
+     * @param mixed $k
+     *
+     * @return bool
+     */
+    protected static function isAcceptedCountable($arg, $k)
+    {
+        if (
+            ((is_numeric($arg)) && (!is_string($arg))) ||
+            ((is_numeric($arg)) && (!Functions::isCellValue($k)) &&
+                (Functions::getCompatibilityMode() !== Functions::COMPATIBILITY_GNUMERIC))
+        ) {
+            return true;
+        }
+
+        return false;
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/Averages.php b/src/PhpSpreadsheet/Calculation/Statistical/Averages.php
new file mode 100644
index 00000000..14c9fef2
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/Averages.php
@@ -0,0 +1,137 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Averages extends AggregateBase
+{
+    /**
+     * AVEDEV.
+     *
+     * Returns the average of the absolute deviations of data points from their mean.
+     * AVEDEV is a measure of the variability in a data set.
+     *
+     * Excel Function:
+     *        AVEDEV(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string (string if result is an error)
+     */
+    public static function AVEDEV(...$args)
+    {
+        $aArgs = Functions::flattenArrayIndexed($args);
+
+        // Return value
+        $returnValue = 0;
+
+        $aMean = self::AVERAGE(...$args);
+        if ($aMean === Functions::DIV0()) {
+            return Functions::NAN();
+        } elseif ($aMean === Functions::VALUE()) {
+            return Functions::VALUE();
+        }
+
+        $aCount = 0;
+        foreach ($aArgs as $k => $arg) {
+            $arg = self::testAcceptedBoolean($arg, $k);
+            // Is it a numeric value?
+            // Strings containing numeric values are only counted if they are string literals (not cell values)
+            //    and then only in MS Excel and in Open Office, not in Gnumeric
+            if ((is_string($arg)) && (!is_numeric($arg)) && (!Functions::isCellValue($k))) {
+                return Functions::VALUE();
+            }
+            if (self::isAcceptedCountable($arg, $k)) {
+                $returnValue += abs($arg - $aMean);
+                ++$aCount;
+            }
+        }
+
+        // Return
+        if ($aCount === 0) {
+            return Functions::DIV0();
+        }
+
+        return $returnValue / $aCount;
+    }
+
+    /**
+     * AVERAGE.
+     *
+     * Returns the average (arithmetic mean) of the arguments
+     *
+     * Excel Function:
+     *        AVERAGE(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string (string if result is an error)
+     */
+    public static function AVERAGE(...$args)
+    {
+        $returnValue = $aCount = 0;
+
+        // Loop through arguments
+        foreach (Functions::flattenArrayIndexed($args) as $k => $arg) {
+            $arg = self::testAcceptedBoolean($arg, $k);
+            // Is it a numeric value?
+            // Strings containing numeric values are only counted if they are string literals (not cell values)
+            //    and then only in MS Excel and in Open Office, not in Gnumeric
+            if ((is_string($arg)) && (!is_numeric($arg)) && (!Functions::isCellValue($k))) {
+                return Functions::VALUE();
+            }
+            if (self::isAcceptedCountable($arg, $k)) {
+                $returnValue += $arg;
+                ++$aCount;
+            }
+        }
+
+        // Return
+        if ($aCount > 0) {
+            return $returnValue / $aCount;
+        }
+
+        return Functions::DIV0();
+    }
+
+    /**
+     * AVERAGEA.
+     *
+     * Returns the average of its arguments, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        AVERAGEA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string (string if result is an error)
+     */
+    public static function AVERAGEA(...$args)
+    {
+        $returnValue = null;
+
+        $aCount = 0;
+        // Loop through arguments
+        foreach (Functions::flattenArrayIndexed($args) as $k => $arg) {
+            if ((is_bool($arg)) && (!Functions::isMatrixValue($k))) {
+            } else {
+                if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
+                    if (is_bool($arg)) {
+                        $arg = (int) $arg;
+                    } elseif (is_string($arg)) {
+                        $arg = 0;
+                    }
+                    $returnValue += $arg;
+                    ++$aCount;
+                }
+            }
+        }
+
+        if ($aCount > 0) {
+            return $returnValue / $aCount;
+        }
+
+        return Functions::DIV0();
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/Counts.php b/src/PhpSpreadsheet/Calculation/Statistical/Counts.php
new file mode 100644
index 00000000..13e7af79
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/Counts.php
@@ -0,0 +1,95 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Counts extends AggregateBase
+{
+    /**
+     * COUNT.
+     *
+     * Counts the number of cells that contain numbers within the list of arguments
+     *
+     * Excel Function:
+     *        COUNT(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return int
+     */
+    public static function COUNT(...$args)
+    {
+        $returnValue = 0;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArrayIndexed($args);
+        foreach ($aArgs as $k => $arg) {
+            $arg = self::testAcceptedBoolean($arg, $k);
+            // Is it a numeric value?
+            // Strings containing numeric values are only counted if they are string literals (not cell values)
+            //    and then only in MS Excel and in Open Office, not in Gnumeric
+            if (self::isAcceptedCountable($arg, $k)) {
+                ++$returnValue;
+            }
+        }
+
+        return $returnValue;
+    }
+
+    /**
+     * COUNTA.
+     *
+     * Counts the number of cells that are not empty within the list of arguments
+     *
+     * Excel Function:
+     *        COUNTA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return int
+     */
+    public static function COUNTA(...$args)
+    {
+        $returnValue = 0;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArrayIndexed($args);
+        foreach ($aArgs as $k => $arg) {
+            // Nulls are counted if literals, but not if cell values
+            if ($arg !== null || (!Functions::isCellValue($k))) {
+                ++$returnValue;
+            }
+        }
+
+        return $returnValue;
+    }
+
+    /**
+     * COUNTBLANK.
+     *
+     * Counts the number of empty cells within the list of arguments
+     *
+     * Excel Function:
+     *        COUNTBLANK(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return int
+     */
+    public static function COUNTBLANK(...$args)
+    {
+        $returnValue = 0;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArray($args);
+        foreach ($aArgs as $arg) {
+            // Is it a blank cell?
+            if (($arg === null) || ((is_string($arg)) && ($arg == ''))) {
+                ++$returnValue;
+            }
+        }
+
+        return $returnValue;
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/MaxMinBase.php b/src/PhpSpreadsheet/Calculation/Statistical/MaxMinBase.php
new file mode 100644
index 00000000..bd17b062
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/MaxMinBase.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+abstract class MaxMinBase
+{
+    protected static function datatypeAdjustmentAllowStrings($value)
+    {
+        if (is_bool($value)) {
+            return (int) $value;
+        } elseif (is_string($value)) {
+            return 0;
+        }
+
+        return $value;
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/Maximum.php b/src/PhpSpreadsheet/Calculation/Statistical/Maximum.php
new file mode 100644
index 00000000..6d361e03
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/Maximum.php
@@ -0,0 +1,78 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Maximum extends MaxMinBase
+{
+    /**
+     * MAX.
+     *
+     * MAX returns the value of the element of the values passed that has the highest value,
+     *        with negative numbers considered smaller than positive numbers.
+     *
+     * Excel Function:
+     *        MAX(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float
+     */
+    public static function MAX(...$args)
+    {
+        $returnValue = null;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArray($args);
+        foreach ($aArgs as $arg) {
+            // Is it a numeric value?
+            if ((is_numeric($arg)) && (!is_string($arg))) {
+                if (($returnValue === null) || ($arg > $returnValue)) {
+                    $returnValue = $arg;
+                }
+            }
+        }
+
+        if ($returnValue === null) {
+            return 0;
+        }
+
+        return $returnValue;
+    }
+
+    /**
+     * MAXA.
+     *
+     * Returns the greatest value in a list of arguments, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        MAXA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float
+     */
+    public static function MAXA(...$args)
+    {
+        $returnValue = null;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArray($args);
+        foreach ($aArgs as $arg) {
+            // Is it a numeric value?
+            if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
+                $arg = self::datatypeAdjustmentAllowStrings($arg);
+                if (($returnValue === null) || ($arg > $returnValue)) {
+                    $returnValue = $arg;
+                }
+            }
+        }
+
+        if ($returnValue === null) {
+            return 0;
+        }
+
+        return $returnValue;
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/Minimum.php b/src/PhpSpreadsheet/Calculation/Statistical/Minimum.php
new file mode 100644
index 00000000..bd46882e
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/Minimum.php
@@ -0,0 +1,78 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Minimum extends MaxMinBase
+{
+    /**
+     * MIN.
+     *
+     * MIN returns the value of the element of the values passed that has the smallest value,
+     *        with negative numbers considered smaller than positive numbers.
+     *
+     * Excel Function:
+     *        MIN(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float
+     */
+    public static function MIN(...$args)
+    {
+        $returnValue = null;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArray($args);
+        foreach ($aArgs as $arg) {
+            // Is it a numeric value?
+            if ((is_numeric($arg)) && (!is_string($arg))) {
+                if (($returnValue === null) || ($arg < $returnValue)) {
+                    $returnValue = $arg;
+                }
+            }
+        }
+
+        if ($returnValue === null) {
+            return 0;
+        }
+
+        return $returnValue;
+    }
+
+    /**
+     * MINA.
+     *
+     * Returns the smallest value in a list of arguments, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        MINA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float
+     */
+    public static function MINA(...$args)
+    {
+        $returnValue = null;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArray($args);
+        foreach ($aArgs as $arg) {
+            // Is it a numeric value?
+            if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
+                $arg = self::datatypeAdjustmentAllowStrings($arg);
+                if (($returnValue === null) || ($arg < $returnValue)) {
+                    $returnValue = $arg;
+                }
+            }
+        }
+
+        if ($returnValue === null) {
+            return 0;
+        }
+
+        return $returnValue;
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/StandardDeviations.php b/src/PhpSpreadsheet/Calculation/Statistical/StandardDeviations.php
new file mode 100644
index 00000000..28a25a75
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/StandardDeviations.php
@@ -0,0 +1,181 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class StandardDeviations extends VarianceBase
+{
+    /**
+     * STDEV.
+     *
+     * Estimates standard deviation based on a sample. The standard deviation is a measure of how
+     *        widely values are dispersed from the average value (the mean).
+     *
+     * Excel Function:
+     *        STDEV(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string The result, or a string containing an error
+     */
+    public static function STDEV(...$args)
+    {
+        $aArgs = Functions::flattenArrayIndexed($args);
+
+        $aMean = Averages::AVERAGE($aArgs);
+
+        if (!is_string($aMean)) {
+            $returnValue = 0.0;
+            $aCount = -1;
+
+            foreach ($aArgs as $k => $arg) {
+                if (
+                    (is_bool($arg)) &&
+                    ((!Functions::isCellValue($k)) || (Functions::getCompatibilityMode() == Functions::COMPATIBILITY_OPENOFFICE))
+                ) {
+                    $arg = (int) $arg;
+                }
+                // Is it a numeric value?
+                if ((is_numeric($arg)) && (!is_string($arg))) {
+                    $returnValue += ($arg - $aMean) ** 2;
+                    ++$aCount;
+                }
+            }
+
+            if ($aCount > 0) {
+                return sqrt($returnValue / $aCount);
+            }
+        }
+
+        return Functions::DIV0();
+    }
+
+    /**
+     * STDEVA.
+     *
+     * Estimates standard deviation based on a sample, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        STDEVA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string
+     */
+    public static function STDEVA(...$args)
+    {
+        $aArgs = Functions::flattenArrayIndexed($args);
+
+        $aMean = Averages::AVERAGEA($aArgs);
+
+        if (!is_string($aMean)) {
+            $returnValue = 0.0;
+            $aCount = -1;
+
+            foreach ($aArgs as $k => $arg) {
+                if ((is_bool($arg)) && (!Functions::isMatrixValue($k))) {
+                } else {
+                    // Is it a numeric value?
+                    if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
+                        $arg = self::datatypeAdjustmentAllowStrings($arg);
+                        $returnValue += ($arg - $aMean) ** 2;
+                        ++$aCount;
+                    }
+                }
+            }
+
+            if ($aCount > 0) {
+                return sqrt($returnValue / $aCount);
+            }
+        }
+
+        return Functions::DIV0();
+    }
+
+    /**
+     * STDEVP.
+     *
+     * Calculates standard deviation based on the entire population
+     *
+     * Excel Function:
+     *        STDEVP(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string
+     */
+    public static function STDEVP(...$args)
+    {
+        $aArgs = Functions::flattenArrayIndexed($args);
+
+        $aMean = Averages::AVERAGE($aArgs);
+
+        if (!is_string($aMean)) {
+            $returnValue = 0.0;
+            $aCount = 0;
+
+            foreach ($aArgs as $k => $arg) {
+                if (
+                    (is_bool($arg)) &&
+                    ((!Functions::isCellValue($k)) || (Functions::getCompatibilityMode() == Functions::COMPATIBILITY_OPENOFFICE))
+                ) {
+                    $arg = (int) $arg;
+                }
+                // Is it a numeric value?
+                if ((is_numeric($arg)) && (!is_string($arg))) {
+                    $returnValue += ($arg - $aMean) ** 2;
+                    ++$aCount;
+                }
+            }
+
+            if ($aCount > 0) {
+                return sqrt($returnValue / $aCount);
+            }
+        }
+
+        return Functions::DIV0();
+    }
+
+    /**
+     * STDEVPA.
+     *
+     * Calculates standard deviation based on the entire population, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        STDEVPA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string
+     */
+    public static function STDEVPA(...$args)
+    {
+        $aArgs = Functions::flattenArrayIndexed($args);
+
+        $aMean = Averages::AVERAGEA($aArgs);
+
+        if (!is_string($aMean)) {
+            $returnValue = 0.0;
+            $aCount = 0;
+
+            foreach ($aArgs as $k => $arg) {
+                if ((is_bool($arg)) && (!Functions::isMatrixValue($k))) {
+                } else {
+                    // Is it a numeric value?
+                    if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
+                        $arg = self::datatypeAdjustmentAllowStrings($arg);
+                        $returnValue += ($arg - $aMean) ** 2;
+                        ++$aCount;
+                    }
+                }
+            }
+
+            if ($aCount > 0) {
+                return sqrt($returnValue / $aCount);
+            }
+        }
+
+        return Functions::DIV0();
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/VarianceBase.php b/src/PhpSpreadsheet/Calculation/Statistical/VarianceBase.php
new file mode 100644
index 00000000..9762ec84
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/VarianceBase.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+abstract class VarianceBase
+{
+    protected static function datatypeAdjustmentAllowStrings($value)
+    {
+        if (is_bool($value)) {
+            return (int) $value;
+        } elseif (is_string($value)) {
+            return 0;
+        }
+
+        return $value;
+    }
+
+    protected static function datatypeAdjustmentBooleans($value)
+    {
+        if (is_bool($value)) {
+            return (int) $value;
+        }
+
+        return $value;
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/Variances.php b/src/PhpSpreadsheet/Calculation/Statistical/Variances.php
new file mode 100644
index 00000000..78b08da9
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/Variances.php
@@ -0,0 +1,183 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Variances extends VarianceBase
+{
+    /**
+     * VAR.
+     *
+     * Estimates variance based on a sample.
+     *
+     * Excel Function:
+     *        VAR(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string (string if result is an error)
+     */
+    public static function VAR(...$args)
+    {
+        $returnValue = Functions::DIV0();
+
+        $summerA = $summerB = 0.0;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArray($args);
+        $aCount = 0;
+        foreach ($aArgs as $arg) {
+            $arg = self::datatypeAdjustmentBooleans($arg);
+            // Is it a numeric value?
+            if ((is_numeric($arg)) && (!is_string($arg))) {
+                $summerA += ($arg * $arg);
+                $summerB += $arg;
+                ++$aCount;
+            }
+        }
+
+        if ($aCount > 1) {
+            $summerA *= $aCount;
+            $summerB *= $summerB;
+
+            return ($summerA - $summerB) / ($aCount * ($aCount - 1));
+        }
+
+        return $returnValue;
+    }
+
+    /**
+     * VARA.
+     *
+     * Estimates variance based on a sample, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        VARA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string (string if result is an error)
+     */
+    public static function VARA(...$args)
+    {
+        $returnValue = Functions::DIV0();
+
+        $summerA = $summerB = 0.0;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArrayIndexed($args);
+        $aCount = 0;
+        foreach ($aArgs as $k => $arg) {
+            if ((is_string($arg)) && (Functions::isValue($k))) {
+                return Functions::VALUE();
+            } elseif ((is_string($arg)) && (!Functions::isMatrixValue($k))) {
+            } else {
+                // Is it a numeric value?
+                if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) & ($arg != '')))) {
+                    $arg = self::datatypeAdjustmentAllowStrings($arg);
+                    $summerA += ($arg * $arg);
+                    $summerB += $arg;
+                    ++$aCount;
+                }
+            }
+        }
+
+        if ($aCount > 1) {
+            $summerA *= $aCount;
+            $summerB *= $summerB;
+
+            return ($summerA - $summerB) / ($aCount * ($aCount - 1));
+        }
+
+        return $returnValue;
+    }
+
+    /**
+     * VARP.
+     *
+     * Calculates variance based on the entire population
+     *
+     * Excel Function:
+     *        VARP(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string (string if result is an error)
+     */
+    public static function VARP(...$args)
+    {
+        // Return value
+        $returnValue = Functions::DIV0();
+
+        $summerA = $summerB = 0.0;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArray($args);
+        $aCount = 0;
+        foreach ($aArgs as $arg) {
+            $arg = self::datatypeAdjustmentBooleans($arg);
+            // Is it a numeric value?
+            if ((is_numeric($arg)) && (!is_string($arg))) {
+                $summerA += ($arg * $arg);
+                $summerB += $arg;
+                ++$aCount;
+            }
+        }
+
+        if ($aCount > 0) {
+            $summerA *= $aCount;
+            $summerB *= $summerB;
+
+            return ($summerA - $summerB) / ($aCount * $aCount);
+        }
+
+        return $returnValue;
+    }
+
+    /**
+     * VARPA.
+     *
+     * Calculates variance based on the entire population, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        VARPA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string (string if result is an error)
+     */
+    public static function VARPA(...$args)
+    {
+        $returnValue = Functions::DIV0();
+
+        $summerA = $summerB = 0.0;
+
+        // Loop through arguments
+        $aArgs = Functions::flattenArrayIndexed($args);
+        $aCount = 0;
+        foreach ($aArgs as $k => $arg) {
+            if ((is_string($arg)) && (Functions::isValue($k))) {
+                return Functions::VALUE();
+            } elseif ((is_string($arg)) && (!Functions::isMatrixValue($k))) {
+            } else {
+                // Is it a numeric value?
+                if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) & ($arg != '')))) {
+                    $arg = self::datatypeAdjustmentAllowStrings($arg);
+                    $summerA += ($arg * $arg);
+                    $summerB += $arg;
+                    ++$aCount;
+                }
+            }
+        }
+
+        if ($aCount > 0) {
+            $summerA *= $aCount;
+            $summerB *= $summerB;
+
+            return ($summerA - $summerB) / ($aCount * $aCount);
+        }
+
+        return $returnValue;
+    }
+}
diff --git a/src/PhpSpreadsheet/Writer/Pdf/Tcpdf.php b/src/PhpSpreadsheet/Writer/Pdf/Tcpdf.php
index 7530b1ef..56e917e3 100644
--- a/src/PhpSpreadsheet/Writer/Pdf/Tcpdf.php
+++ b/src/PhpSpreadsheet/Writer/Pdf/Tcpdf.php
@@ -24,7 +24,7 @@ class Tcpdf extends Pdf
      *
      * @param string $orientation Page orientation
      * @param string $unit Unit measure
-     * @param string $paperSize Paper size
+     * @param array|string $paperSize Paper size
      *
      * @return \TCPDF implementation
      */
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevATest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevATest.php
new file mode 100644
index 00000000..9115db46
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevATest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class StDevATest extends TestCase
+{
+    /**
+     * @dataProvider providerSTDEVA
+     *
+     * @param mixed $expectedResult
+     * @param mixed $values
+     */
+    public function testSTDEVA($expectedResult, $values): void
+    {
+        $result = Statistical::STDEVA($values);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerSTDEVA()
+    {
+        return require 'tests/data/Calculation/Statistical/STDEVA.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevPATest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevPATest.php
new file mode 100644
index 00000000..9d8921cc
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevPATest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class StDevPATest extends TestCase
+{
+    /**
+     * @dataProvider providerSTDEVPA
+     *
+     * @param mixed $expectedResult
+     * @param mixed $values
+     */
+    public function testSTDEVPA($expectedResult, $values): void
+    {
+        $result = Statistical::STDEVPA($values);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerSTDEVPA()
+    {
+        return require 'tests/data/Calculation/Statistical/STDEVPA.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevPTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevPTest.php
new file mode 100644
index 00000000..47b058b3
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevPTest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class StDevPTest extends TestCase
+{
+    /**
+     * @dataProvider providerSTDEVP
+     *
+     * @param mixed $expectedResult
+     * @param mixed $values
+     */
+    public function testSTDEVP($expectedResult, $values): void
+    {
+        $result = Statistical::STDEVP($values);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerSTDEVP()
+    {
+        return require 'tests/data/Calculation/Statistical/STDEVP.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevTest.php
new file mode 100644
index 00000000..6a96fa2f
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/StDevTest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class StDevTest extends TestCase
+{
+    /**
+     * @dataProvider providerSTDEV
+     *
+     * @param mixed $expectedResult
+     * @param mixed $values
+     */
+    public function testSTDEV($expectedResult, $values): void
+    {
+        $result = Statistical::STDEV($values);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerSTDEV()
+    {
+        return require 'tests/data/Calculation/Statistical/STDEV.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarATest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarATest.php
new file mode 100644
index 00000000..1b8b676f
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarATest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class VarATest extends TestCase
+{
+    /**
+     * @dataProvider providerVARA
+     *
+     * @param mixed $expectedResult
+     * @param mixed $values
+     */
+    public function testVARA($expectedResult, $values): void
+    {
+        $result = Statistical::VARA($values);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerVARA()
+    {
+        return require 'tests/data/Calculation/Statistical/VARA.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarPATest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarPATest.php
new file mode 100644
index 00000000..ee0cfee6
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarPATest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class VarPATest extends TestCase
+{
+    /**
+     * @dataProvider providerVARPA
+     *
+     * @param mixed $expectedResult
+     * @param mixed $values
+     */
+    public function testVARPA($expectedResult, $values): void
+    {
+        $result = Statistical::VARPA($values);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerVARPA()
+    {
+        return require 'tests/data/Calculation/Statistical/VARPA.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarPTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarPTest.php
new file mode 100644
index 00000000..fe3af037
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarPTest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class VarPTest extends TestCase
+{
+    /**
+     * @dataProvider providerVARP
+     *
+     * @param mixed $expectedResult
+     * @param mixed $values
+     */
+    public function testVARP($expectedResult, $values): void
+    {
+        $result = Statistical::VARP($values);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerVARP()
+    {
+        return require 'tests/data/Calculation/Statistical/VARP.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarTest.php
new file mode 100644
index 00000000..aa25f5cc
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/VarTest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class VarTest extends TestCase
+{
+    /**
+     * @dataProvider providerVAR
+     *
+     * @param mixed $expectedResult
+     * @param mixed $values
+     */
+    public function testVAR($expectedResult, $values): void
+    {
+        $result = Statistical::VARFunc($values);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerVAR()
+    {
+        return require 'tests/data/Calculation/Statistical/VAR.php';
+    }
+}
diff --git a/tests/data/Calculation/Statistical/STDEV.php b/tests/data/Calculation/Statistical/STDEV.php
new file mode 100644
index 00000000..846f8c71
--- /dev/null
+++ b/tests/data/Calculation/Statistical/STDEV.php
@@ -0,0 +1,12 @@
+<?php
+
+return [
+    [
+        27.463915719843,
+        [1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299],
+    ],
+    [
+        '#DIV/0!',
+        ['A', 'B', 'C'],
+    ],
+];
diff --git a/tests/data/Calculation/Statistical/STDEVA.php b/tests/data/Calculation/Statistical/STDEVA.php
new file mode 100644
index 00000000..9fd45d65
--- /dev/null
+++ b/tests/data/Calculation/Statistical/STDEVA.php
@@ -0,0 +1,12 @@
+<?php
+
+return [
+    [
+        27.463915719843,
+        [1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299],
+    ],
+    [
+        '#DIV/0!',
+        [],
+    ],
+];
diff --git a/tests/data/Calculation/Statistical/STDEVP.php b/tests/data/Calculation/Statistical/STDEVP.php
new file mode 100644
index 00000000..03f63e08
--- /dev/null
+++ b/tests/data/Calculation/Statistical/STDEVP.php
@@ -0,0 +1,12 @@
+<?php
+
+return [
+    [
+        26.0545581424825,
+        [1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299],
+    ],
+    [
+        '#DIV/0!',
+        ['A', 'B', 'C'],
+    ],
+];
diff --git a/tests/data/Calculation/Statistical/STDEVPA.php b/tests/data/Calculation/Statistical/STDEVPA.php
new file mode 100644
index 00000000..9c331285
--- /dev/null
+++ b/tests/data/Calculation/Statistical/STDEVPA.php
@@ -0,0 +1,12 @@
+<?php
+
+return [
+    [
+        26.0545581424825,
+        [1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299],
+    ],
+    [
+        '#DIV/0!',
+        [],
+    ],
+];
diff --git a/tests/data/Calculation/Statistical/VAR.php b/tests/data/Calculation/Statistical/VAR.php
new file mode 100644
index 00000000..255034ff
--- /dev/null
+++ b/tests/data/Calculation/Statistical/VAR.php
@@ -0,0 +1,8 @@
+<?php
+
+return [
+    [
+        754.266666666667,
+        [1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299],
+    ],
+];
diff --git a/tests/data/Calculation/Statistical/VARA.php b/tests/data/Calculation/Statistical/VARA.php
new file mode 100644
index 00000000..255034ff
--- /dev/null
+++ b/tests/data/Calculation/Statistical/VARA.php
@@ -0,0 +1,8 @@
+<?php
+
+return [
+    [
+        754.266666666667,
+        [1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299],
+    ],
+];
diff --git a/tests/data/Calculation/Statistical/VARP.php b/tests/data/Calculation/Statistical/VARP.php
new file mode 100644
index 00000000..177b8477
--- /dev/null
+++ b/tests/data/Calculation/Statistical/VARP.php
@@ -0,0 +1,8 @@
+<?php
+
+return [
+    [
+        678.84,
+        [1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299],
+    ],
+];
diff --git a/tests/data/Calculation/Statistical/VARPA.php b/tests/data/Calculation/Statistical/VARPA.php
new file mode 100644
index 00000000..177b8477
--- /dev/null
+++ b/tests/data/Calculation/Statistical/VARPA.php
@@ -0,0 +1,8 @@
+<?php
+
+return [
+    [
+        678.84,
+        [1345, 1301, 1368, 1322, 1310, 1370, 1318, 1350, 1303, 1299],
+    ],
+];