Suppose you are interested in measuring the amount of time on average it takes you to make your commute to school. Over 18 random days, you estimated that the average time is 38.4 minutes with a standard deviation of 5.362 minutes. (a) Construct a 90% confidence interval for the mean commute time to school. Round your answers to two decimal places. (b) How many measurements must be averaged to get a margin of error of 0.05 with 90% confidence? (c) Assuming n=84, construct a 90% confidence interval for the mean commute time to school.

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