We ran a A/B test for all the customers and there are two sub groups within each group. How do I determine statistically conversion lift in one group is greater than conversion lift in other group.
For example. Control group (Higher income group, lower income group): out of 100 customers in each group, 20 and 50 purchased the product respectively. Conversion rate(Higher income - control) = 20%, Conversion rate(Lower income - Control) = 50%
Test group (Higher income group, lower income group): out of 100 customers in each group, 40 and 70 purchased the product respectively. Conversion rate(Higher income - Test) = 40%, Conversion rate(Lower income - Test) = 70% Conversion lift in Higher income group = (40 - 20)/20 = 100% Conversion lift in lower income group = (70 - 50)/50 = 40%
How to determine if the lift in higher income group is statistically significant?