* Use validation classes rather than traits for Statistical functions, and some verification of nullable arguments
* Eliminate more of the issues resolved in phpstan baseline
* Additional unit tests and rationalisation for Financial Functions
* Providing a series of sample files for Financial functions
* Refactor the last of the existing Financial functions
* Some more unit tests with default assignments from null arguments
Co-authored-by: Adrien Crivelli <adrien.crivelli@gmail.com>
* Extract Normal and Standard Normal Distributions from the Statistical Class
* Extract ZTest from the Statistical Class, and move it to the Standard Normal Distribution class
Additional unit tests for NORMINV()
* Extract LogNormal distribution functions from Statistical
Mark Baker