1. A store repairs cell phones. Repairs to phones under warranty are reimbursed by the manufacturer. Curious whether the manufacturer’s reimbursements are covering the actual repair costs, the store’s manager would like to know the average repair cost. Since a census of all repairs would be impossible, the manager decides to use a sample of 21 repairs and calculate a 95% confidence interval. In the sample, the mean is $45.66 and the standard deviation is $27.79.
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3. 1. Give the lower and upper confidence limits. Round your answers to three decimals.

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In the sample of 21 repairs the mean is 4566 and the standard devi... View the full answer