Question: In the test of the quality of two television commercials, each commercial was shown a separate test area six times over a one-week period. The following week a telephone survey was conducted to identify individuals who had seen the commercials. Those individuals were asked to state the primary message in the commercials. The following results were recorded:

Commercial A Commercial B

Number who saw commercial 150 200

Number who recalled message 63 60

a. use α = .05 and test the hypothesis that there is no difference in the recall proportions for the two commercials.

b. Compute a 95% confidence interval for the difference between the recall proportions for the two populations.