3.46 Diamond prices: nested F-test. Refer to the complete second- order model you found for diamond prices in Exercize 328 ). Use 413 a nested F-test to determine whether all of the terms in the model that involve the information on Depth could be removed as a group from the model with out significantly impairing its effectiveness. Dunend 3.47 Driving fatalities and speed limits. In Exercise 3.32, you considered a multiple regression model to compare the regression lines for highway fatalities versus year between years before and after states assumed control of setting speed limits on interstate highways. The data are in the file Speed with variables for FatalityRate, Year, and an indicator variable StateControl. In Speed a. Use a nested F-test to determine whether there is a significant difference in either the slope and/ or the intercept of those two lines. b. Use a nested F-test to test only for a difference in slopes ( Ho : 83 = ). Compare the results of this test to the to test for that coefficient in the original regression