Refer to the data of Exercise 11.9.
a. Use the regression line of Exercise 11.10 to calculate predicted values for x 5 60, 80, 100, 120, and 140.
b. For which x- values are most of the actual y- values larger than the predicted y- values? For which x- values are most of the actual y- values smaller than the ­predicted y- values? What does this pattern indicate about whether there is a linear relation between the drill speed and the lifetime of the bit?
c. Suggest a transformation of the data to obtain a linear relation between the lifetime of the bit and the transformed values of the drill speed.
In exercise

Transcribed Image Text:

60 0 60 60 80 0 80 80 100 100 y 4.6 38 4.9 45 4.7 58 5.5 5.4 5.0 4.5 x 100 100 120 20 120 120 140 140 140 140 y 3.2 4.8 4. 45 4.0 8 3.6 3.0 3.5 3.4