Refer to Example 10.4 (p. 544). Recall that the USGA wants to compare the mean driving distances of four different golf ball brands (A, B, C, and D). Iron Byron, the USGA’s robotic golfer, is used to hit a sample of 10 balls of each brand. The distance data are reproduced in Table 12.3.

A Model with one Qualitative Independent Variable: Golf Ball Driving Distances Example 12.9

a. Hypothesize a regression model for driving distance y, using Brand as an independent variable.

b. Interpret the b’s in the model.

c. Fit the model to the data and give the least squares prediction equation. Show that the b-estimates can also be obtained from the sample means.

d. Use the model to determine whether the mean driving distances for the four brands are significantly different at a = .05.