# How to Calculate a 95% Confidence Interval

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A random sample of 20 patients in a weight loss clinical trial lost an average of 25 pounds over an 8 week period. The sample standard deviation is 10. What is the 95% confidence interval for the weight loss for all patients included in the weight loss clinical trial?

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#### Solution Preview

In order to find the 95% confidence interval for this question, we will use the following formula:

confidence interval = mean +/- ...

#### Solution Summary

A complete, worked through solution outlining the steps needed to calculate a 95% confidence interval for a specific statistics example.

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