Answered: Pretzels: In order to judge the…

Holt Mcdougal Larson Pre-algebra: Student Edition 2012

1st Edition

ISBN:9780547587776

Author:HOLT MCDOUGAL

Publisher:HOLT MCDOUGAL

Chapter11: Data Analysis And Probability

Section: Chapter Questions

Problem 8CR

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Transcribed Image Text: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 90 convenience store receipts the week before the ad campaign began, and found that 28 of them showed a purchase of the pretzels. Another simple random sample of 70 receipts was taken the week after the ad campaign, and 40 of them showed a pretzel purchase. Part: 0 / 2 Part 1 of 2 (a) Construct an 80% 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. An 80% confidence interval for the difference between the proportion of customers purchasing pretzels before and after the ad campaign is <P1-P2<. Part 2 of 2 (b) A marketing manager claims that the proportion of customers who purchased pretzels did not change after the ad campaign. Does the confidence interval contradict this claim? Because the confidence interval (Choose one) v 0, it (Choose one) customers who purchased pretzels did not change after the ad campaign. the claim that the proportion of

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