VBA code and formulae allowing statistical analysis in MS Excel without add-ons.

AB-Test

1. If test conditions* are met, do a pooled Z test comparing 2 proportions.
2. If test conditions are met and significant difference is found, return the proportion difference.
3. If test conditions are not met, or there is no significant difference, do not return anything.

Usage:

=ABTest_Proportions(n1,y1,n2,y2)

* Test Conditions:

1. n1*p1 > 5
2. n1*(1 - p1) > 5
3. n2 * p2 > 5
4. n2(1 - p2) > 5

Where:

1. n1 - sample size of group 1
2. n2 - sample size of group 2
3. y1 - count of instances of success in group 1
4. y2 - count of instances of success in group 2
5. p1 - proportion of group 1: y1/n1
6. p2 - proportion of group 2: y2/n2