Question

We suspect that the number of callers (and by implication listeners) to a radio talk show has fallen recently. The long-running show has historically had a mean of 100 callers per hour during its run before this year. It is also known, according to past experience, that the distribution of callers per hour has a standard deviation of 10.

a. Set up appropriate null and alternative hypotheses to test whether the number of callers is falling.

b. If a random sample of size n = 36 hours is taken for the last four weeks and a mean of 96 callers per hour is observed, what inference can we draw at (alpha) = 0.05 ? (The t-value for a onetailed test with 35 degrees of freedom and 5% significance is 1.69.)

Answer 1