A clinical trial was conducted to test the effectiveness of a drug used for treating insomnia in older subjects. After treatment with the​ drug, 20 subjects had a mean wake time of 94.3 min and a...

A clinical trial was conducted to test the effectiveness of a drug used for treating insomnia in older subjects. After treatment with the​ drug, 20 subjects had a mean wake time of 94.3 min and a standard deviation of 43.3 min. Assume that the 20 sample values appear to be from a normally distributed population and construct a 95% confidence interval estimate of the standard deviation of the wake times for a population with the drug treatments.Does the result indicate whether the treatment is effective?

Find the confidence interval estimate.

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Round to two decimal places as needed.