Refer to Exercise 41 for a description of reaction and braking distances. Let R be the reaction distance, B be the braking distance, and D be the stopping distance, all in feet, when driving at s miles per hour.
a. The residual plot for using the regression line to model the association between s and R is shown in Fig. 77. What can you conclude about the association?

b. Construct a scatterplot that compares the values of s and R. Does it confirm your response to part (a)?
c. The linear regression equations for reaction, braking, and stopping distances are = 2.2s, = 6.32s - 132.75, and = 8.52s - 132.75, respectively. Show that the sum of the right-hand sides of the first two equations is equal to the right-hand side of the third equation.
d. The residual plots for using regression lines to model the speed-braking and speed-stopping associations are shown in Fig. 78. What do you notice about the residual plots? Why did this happen?

In exercise

Transcribed Image Text:

Driving Speed versus Residual 5 40 30 20 10 8-10 -20 20 30 40 50 60 70 80 90s Driving Speed (mph) Driving Speed versus Residual 50 40 30 a 20 10 9-10 -20 -30 20 30 4 50 60 70 80 90 Driving Speed (mph) Driving Speed versus Residual 30 10 -10 a -20 -30 20 30 40 50 60 70 80 90 Driving Speed (mph) Table 51 Reaction and Braking Distances Driving Speed mles per hour) feet) Reaction Distance Braking Distance (feet 25 57 101 158 227 310 20 30 40 110 132 154 176 70 80