Recall that simple linear regression was used to model y = mass of the spill as a function of x = 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, parts a and b. Which interval is wider? Will this always be the case? Explain.
Exercise 11.26
Refer to the Chemical Engineering Progress (Jan. 2005) study of the rate at which a spilled volatile liquid will spread across a surface. Exercise 2.128. Recall that a DuPont Corp. engineer calculated the mass (in pounds) of a 50-gallon methanol spill after a period of time ranging from 0 to 60 minutes. Do the data in the table below indicate that the mass of the spill tends to diminish as time increases? If so, how much will the mass diminish each minute?

For Information: Refer to the Chemical Engineering Progress (Jan. 2005) study of the rate at which a spilled volatile liquid will spread across a surface. Exercise 11.26.

60778047620 19631000 226 28 30 35 40 45 50 5 60 64 34 04 47 94 44 98 55 741 Mo 666544333222 THE 4 6 8 12 14 16 18