An appliance chain displays a prominent ad for a "great sale on our most popular washing machine." This ad appears in the physical stores and on the company's website. Two random samples of shoppers are chosen. The first sample consists of 500 shoppers who shop predominantly at one of the chain's physical stores. The second sample consists of 300 shoppers who shop predominantly online at the company's website. Suppose that 45 shoppers from the in-store sample purchase the washing machine, and 11 shoppers from the online sample purchase the washing machine. Let p1 be the proportion of all in-store shoppers who purchase the washing machine, and let p2 be the similar proportion for all online shoppers. The endpoints of a 95% confidence interval for p1-p2 are closest to which of the following?

a. 0.020 to 0.086

b. 0.010 to 0.097

c. 0.016 to 0.091

d. 0.026 to 0.081

Answer rating: 100% (QA)

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