I am performing an A(control) vs B(variant) test twice. I want to know if the difference of A/B change between the 2 runs is statistically significant.
Example:
1st run:
both A and B have 100 data points each
conversion(A)=12% , conversion(B)=15% => change=25%
2nd run:
both A and B have 80 data points each
conversion(A)=10%, conversion(B)=12% => change=20%
What test to apply to know if the difference between 25% and 20% is significant?