This week we extend that set of tools to two sample tests.However, here we have a greater variety of tests.For the t-test alone there are three variants based on the independence of the groups and whether we can assume variances the same or variances between the groups as different.The variances issue is easy as we can always assume they are different as the test is robust to accept any variances but the dependent pairs is different.Why is it different and how might you use it?