Spreading rate of spilled liquid. Refer to the Chemicial Engineering Progress (Jan. 2005) study of the rate at which a spilled volatile liquid will spread across a surface, presented in Exercise 11.35

(p. 630). Recall that simple linear regression was used to model y = mass of the spill as a function of y = elapsed time of the spill.

a. Find a 99% confidence interval for the mean mass of all spills with an elapsed time of 15 minutes. Interpret the result.

b. Find a 99% prediction interval for the mass of a single spill with an elapsed time of 15 minutes. Interpret the result.

c. Compare the intervals you found in parts a and b.

Which interval is wider? Will this always be the case?

Explain.