When two population means are equal, evaluated standard error for independent measures t-test gives measure of how much difference to expect between two sample means. For each of given situations suppose that µ1 = µ2 and ciompute how much difference must be expected between two sample means.

a. one sample has n=8 scores with SS=45 and second sample has n=4 scores with SS=15.

b. one sample has n=8 scores with SS=150 and second sample has n=4 scores with SS=90

c. in part b, sample have greater variability than part a, but sample sizes are unchanged. How does larger variability influence size of standard error for sample mean?