Use the data in Exercise 25 in Section 13.1 for the following.

a. Compute a point estimate for the mean vertical expansion at locations where the horizontal expansion is 25.

b. Construct a 99% confidence interval for the mean vertical expansion at locations where the horizontal expansion is 25.

c. Predict the vertical expansion at a particular location where the horizontal expansion is 25.

d. Construct a 99% prediction interval for the vertical expansion at a particular location where the horizontal expansion is 25.

Exercise 25

Concrete expands both horizontally and vertically over time. Measurements of horizontal and vertical expansion (in units of parts per hundred thousand) were made at several locations on a bridge in Quebec City in Canada. The results are presented in the following table.

Horizontal Vertical 20 58 15 58 43 55 5 80 18 58 24 68 32 57 10 69 21 63