For each of the following, calculate the pooled variance and the estimated standard error for the sample mean difference
a. The first sample has n=4 scores and a variance of s2 = 17, and the second sample has n=8 scores and a variance of s2 = 27.
b. Now the sample variances are increased so that the first sample has n=4 scores and the a variance of s2 = 68, and the second has n= 8 scores and a variance of s2= 108
c. Comparing your answers for parts a and b, how does increased variance influence the size of the estimated standard error?