Pretzels: In order to judge the effectiveness of an advertising campaign for a certain brand of pretzel, a company obtained a simple random sample of 92 convenience store receipts the week before the ad campaign began, and found that 27 of them showed a purchase of the pretzels. Another simple random
sample of 72 receipts was taken the week after the ad campaign, and 41 of them showed a pretzel purchase.
Part: 0/2
Part 1 of 2
(a) Construct a 90% confidence interval for the difference between the proportions of customers purchasing pretzels before and after the ad campaign.
Let P, denote the proportion of customers purchasing pretzels before the ad campaign and let P, denote the proportion of customers purchasing pretzels
after the ad campaign. Use the TI-84 Plus calculator and round the answers to three decimal places.
A 90% confidence interval for the difference between the proportion of customers purchasing pretzels before and after the
ad campalgn is X