46. Reconsider the ltration rate—moisture content data introduced in Example 12.7 (see also Example 12.8).

a. Compute a 90% CI for b0  125b1, true average moisture content when the ltration rate is 125.

b. Predict the value of moisture content for a single experimental run in which the ltration 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 ltration rate is 115?

Answer without actually calculating these new intervals.

d. Interpret the hypotheses H0: b0  125b1  80 and H0: b0  125b1  80, and then carry out a test at signi cance level .01.