The following table presents the speed (in mph) and the stopping distance (in feet) for a sample of cars.

a. Compute the least-squares regression line for predicting stopping distance (y) from speed (x).

b. Construct a residual plot. Explain why the least-squares line is not an appropriate summary of the data.

c. For each data point, square the speed. This is x2. Compute the least-squares regression line for predicting distance y from x2.

d. Construct a residual plot. Is this line an appropriate summary?

e. Use the equation computed in part

(c) to predict the stopping distance for a car whose speed is 15 mph.

Transcribed Image Text:

Speed Distance Speed Distance 4 12 16 44 7 14 17 48 8 19 18 49 9 20 19 57 10 18 20 59 11 22 22 75 12 25 23 78 13 32 24 14 38 25 88 87 90 15 38