[AccessD] Calculate quartiles

[Gustav Brock]

Hi all

For some strange reason, my latest article and code project is about quartiles and medians. 
It features a main function and two domain-type functions:

 - Quartile
 - DQuartile
 - DMedian

While calculating the median is easy, there is no single "correct" calculation method for quartiles. Excel features two methods, some math and statistic packages offer some more. In total, I have located no less than twenty methods for various purposes:

    https://www.experts-exchange.com/articles/33718/20-Varieties-of-Quartiles.html

If you don't have an account, browse for the link: Read the full article.

Code is also on GitHub: 

    https://github.com/GustavBrock/VBA.Quartiles

The documentation on calculation methods to find is sparse, so comments are most welcome.

/gustav