Pretzels: In order to judge the effectiveness of an

Last updated: 7/8/2022

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 100 convenience store receipts the week before the ad campaign began, and found that 21 of them showed a purchase of the pretzels. Another simple random 30 sample of 80 receipts was taken the week after the ad campaign, and of them showed a pretzel purchase. Part: 0/2 Part 1 of 2 (a) Construct a 99.9% confidence interval for the difference between the proportions of customers purchasing pretzels before and after the ad campaign. Let P₁ denote the proportion of customers purchasing pretzels before the ad campaign. Use tables to find the critical value and round the answer to at least three decimal places. A 99.9% confident that the difference between the proportions of customers purchasing pretzels before and after the ad campaign is <P₁ P₂ <0. X 3