A company that has many department stores in the southern states wanted to find at two such stores the percentage of sales for which at least one of the items was returned. A sample of 800 sales randomly selected from Store A showed that for 280 of them at least one item was returned. Another sample of 900 sales randomly selected from Store B showed that for 279 of them at least one item was returned. a. Construct a 98% confidence interval for the difference between the proportions of all sales at the two stores for which at least one item is returned. b. Using the 10% significance level, can you conclude that the proportions of all sales for which at least one item is returned is higher for Store A than for Store B?
A company that has many department stores in the southern states wanted to find at two such stores the percentage of sales for which at least one of the items was returned. A sample of 800 sales randomly selected from Store A showed that for 280 of them at least one item was returned. Another sample of 900 sales randomly selected from Store B showed that for 279 of them at least one item was returned. a. Construct a 98% confidence interval for the difference between the proportions of all sales at the two stores for which at least one item is returned. b. Using the 10% significance level, can you conclude that the proportions of all sales for which at least one item is returned is higher for Store A than for Store B?
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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Transcribed Image Text:7. A company that has many department stores in the southern states wanted to find at two
such stores the percentage of sales for which at least one of the items was returned. A
sample of 800 sales randomly selected from Store A showed that for 280 of them at least
one item was returned. Another sample of 900 sales randomly selected from Store B
showed that for 279 of them at least one item was returned.
a. Construct a 98% confidence interval for the difference between the proportions of all
sales at the two stores for which at least one item is returned.
b. Using the 10% significance level, can you conclude that the proportions of all sales
for which at least one item is returned is higher for Store A than for Store B?
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