At a certain facility, one net count corresponds to an activity of 12.9 Bq in a sample; and the expected number, 816, of background counts is well known.

a) If the maximum acceptable risk for making a type-I error is 0.050, what is the minimum significant net count?

b) If the minimum detectable true activity is AII = 1300 Bq, what is the risk of making a type-II error when a sample has an activity exactly equal to AII? (Use the approximate formula.)

c) What is the probability of making a type-II error in a single measurement with a sample that has an activity exactly equal to the minimum significant measured activity?

d) If the minimum detectable true activity AII were taken to be the same as the minimum significant measured activity A{, what would be the probability of making a type-II error with a sample having an activity equal to AII?