A clinical trial was conducted to test the effectiveness of a drug used for treating insomnia in older subjects. After treatment with thedrug, 20 subjects had a mean wake time of 97.3 min and a standard deviation of 44.3 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 iseffective?

Find the confidence interval estimate.

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____min < < ___min

(Round to two decimal places asneeded.)