For the data of the previous two exercises, we want a 95% confidence interval for the ratio of population standard deviations. 

Previous Exercise

a. Recall that this method requires the data to be normal, and the method is sensitive to departures from normality. Check the data for normality to see if the F distribution can be used for the ratio of sample variances.

b. Use software to generate a bootstrap sample of ratios of standard deviations. Then use the percentile method to obtain a 95% confidence interval for the ratio of population standard deviations.

c. Compare the two results and discuss the relationship of the results to those of the previous exercise.

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79. A student project by Heather Kral studied students on "lifestyle floors" of a dormitory in comparison to students on other floors. On a lifestyle floor the students share a common major, and there are a faculty coordinator and resident assistant from that department. Here are the GPAs of 30 stu- dents on lifestyle floors (L) and 30 students on other floors (N): L: 2.00 2.25 2.60 2.90 3.00 3.00 3.00 3.00 3.00 3.20 3.20 3.25 3.30 3.30 3.32 3.50 3.50 3.60 3.60 3.70 3.75 3.75 3.79 3.80 3.80 3.90 4.00 4.00 4.00 4.00 N: 1.20 2.00 4.00 2.29 2.45 2.50 2.50 2.50 2.50 2.65 2.70 2.75 2.75 2.79 2.80 2.80 2.86 2.90 3.00 3.07 3.10 3.25 3.50 3.54 3.56 3.60 3.70 3.75 3.80 4.00 2.80