Discussion:
A. Select a variable. Compare the mean of the variable for a sample of 30 for one group with the mean of the variable for a sample of 30 for a second group. Use a z test.
B. Select a variable. Compare the mean of the variable for a sample of 10 for one group with the mean of the variable for a sample of 10 for a second group. Use a t test.
C. Select a variable that will enable you to compare proportions of two groups. Use sample sizes of at least 30. Use the z test for proportions.