# constructing a confidence interval with Excel.

I need to know how to do this using microsoft excel. Do not address this unless you can do it in EXCEL. thank you

Dunkin Donuts advertises that a dozen of their donuts weighs about 43 oz. A certain baker has figured out that she can stay out of trouble with her manager if each donut weighs about 3.6 oz. To test her donut-making process, she randomly selects thirty-one donuts after baking and weighs them. The average of the sample is 3.504 oz with s = 0.109 oz. Construct a 95% confidence interval for the true population mean of donut weights, and then explain whether or not she will be in trouble.

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#### Solution Preview

in the question, mean weight is M=3.6

<br>sample mean is Xm=3.504

<br>sample number N=31

<br>standard deviation is s=0.109

<br>since it's a two-tailed test, we will apply the ...

#### Solution Summary

Problem shows how to calculate a confidence interval in Excel to determine is a confidence interval around a sample mean contains a critical value. A hypothesis test via the confidence interval method.