1)The Concept Behind The 2 Proportions Test

Why do we use the Z-test when comparing proportions? What is a Z-Score?

2)Standard Deviation and Standard Error

What does the standard deviation tell us about our data? How is it different from standard error?

3)Power and Significance in an AB Test

What does significance and power mean in an ab test? What are type I and type II errors?

4)The Mann Whitney Test and It's Use

What measures are suited for a Mann-Whitney test? What is the logic behind this type of testing?