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I keep getting this wrong...anyone who can help step by step?

I keep getting this wrong...anyone who can help step by step?-example-1

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we are given the mean weight of 22 textbooks, and that is 80 ounces. We are also given a standard deviation of 8.7 ounces. We are required to find the population mean with a 95% copnfident. we can use the following formula


\mu=\bar{X}\pm\frac{2\sigma}{\sqrt[]{n}}

Where the greek letter sigma is the standard deviation and "n" is the total population. Replacing the known values we get:


\mu=80\pm\frac{2(8.7)}{\sqrt[]{22}}

Solving for the plus sign


\mu=80+37.1=117.1

Solving for the minus sign


\mu=80-37.1=42.90

The interval

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