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## Find the margin of error and the 90 percent confidence interval for Julias average running time.

Julia enjoys jogging. She has been jogging over a period of several years, during which time her physical condition has remained constantly good. Usually she jogs 2 miles per day. During the past year Julia recorded how long it took her to run 2 miles. She has a random sample of 95 of these times. For these 95 times the mean was 15.60 minutes and the standard deviation s=1.80 minutes. Find the margin of error (round to 2 decimal places) and the 90% confidence interval for Julia’s average running time.