Reconsider the filtration rate–moisture content data introduced in Example 12.6 (see also Example 12.7).

a. Compute a 90% CI for , true average moisture content when the filtration rate is 125.

b. Predict the value of moisture content for a single experimental run in which the filtration rate is 125 using a 90%

prediction level. How does this interval compare to the interval of part (a)? Why is this the case?

c. How would the intervals of parts

(a) and

(b) compare to a CI and PI when filtration rate is 115? Answer without actually calculating these new intervals.

d. Interpret the hypotheses and

, and then carry out a test at significance level .01.