Use the information given in Problem 2 of Chapter 8, as well as the computer output given here, to answer the following questions about the data from that problem.
a. Conduct overall regression F tests for these three models: Y regressed on X1 and X2; Y regressed on X1 alone; and Y regressed on X2 alone. Based on your answers, how would you rate the importance of the two variables in predicting Y? Comment on how your answer compares with the answer to Problem 2(b) in Chapter 8.
b. Provide variables-added-in-order tests for both variables, with thinking disturbances (X1) added first. Use α = .05.
c. Provide variables-added-in-order tests for both variables, with hostile suspiciousness (X2) added first. Use α = .05.
d. Provide a table of variables-added-last tests.
e. What, if any, differences are present in the approaches in parts (a) through (d)?
f. Which predictors appear to be necessary? Why?