73.

a. Use the results of Example 8.5 to obtain a 95%

lower con dence bound for the parameter l of an exponential distribution, and calculate the bound based on the data given in the example.

b. If lifetime X has an exponential distribution, the probability that lifetime exceeds t is P(X t) 

elt. Use the result of part

(a) to obtain a 95%

lower con dence bound for the probability that breakdown time exceeds 100 min.