Question:
Data Set 9 in Appendix B includes 23 movies with ratings of PG or PG-13, and those movies have lengths (in minutes) with a mean of 120.8 min and a standard deviation of 22.9 min. That same data set also includes 12 movies with R ratings, and those movies have lengths with a mean of 118.1 min and a standard deviation of 20.8 min.
a. Construct a 95% confidence interval estimate of the standard deviation of the lengths of all movies with ratings of PG or PG-13.
b. Construct a 95% confidence interval estimate of the standard deviation of the lengths of all movies with ratings of R.
c. Compare the variation of the lengths of movies with ratings of PG or PG-13 to the variation of the lengths of movies with ratings of R. Does there appear to be a difference?
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Data Set 9: Movies STATDISK: Minitab: Excel: TI-83/84 Plus: Text file names: Title 8 Mile Alone in the Dark Aviator Crash Daddy Day Care DaVinci Code Eternal Sunshine From Justin to Kelly Harry Potter Goblet of Fire Hostel House of the Dead Last Samurai Million Dollar Baby Pirates of the Carribbean (II) Rollerball S.W.A.T. Secret Window Signs Silent Hill Big Fish Bourne Identity Break-Up PG-13 Charlie's Angels: Full Throttle PG-13 Collateral Son of the Mask Spider-Man 2 Star Wars III Sum of All Fears The Pianist Data set name is Movies. Worksheet name is MOVIES.MTW. Workbook name is MOVIES.XLS. App name is MOVIES and the file names are the same as for text files. MVBUD, MVGRS, MVLEN, MVRAT. The Village Van Helsing Vanilla Sky Walk the Line War of the Worlds Wedding Crashers MPAA Rating R R PG-13 PG-13 PG-13 R R PG PG-13 R PG PG-13 R R R PG-13 PG-13 PG-13 PG-13 PG-13 PG-13 R PG PG-13 PG-13 PG-13 R PG-13 PG-13 R PG-13 PG-13 R Budget ($) in Millions 41.0 20.0 116.0 70.0 75.0 52.0 120.0 65.0 6.5 60.0 125.0 20.0 5.0 150.0 4.5 7.0 100.0 30.0 225.0 70.0 80.0 40.0 70.0 50.0 74.0 200.0 113.0 68.0 35.0 72.0 160.0 68.0 29.0 132.0 40.0 Gross ($) in Millions 117 5 36016 10 100 5542342 121 104 12 290 47 ៩ដ៩៥៩និង៩ខឹងជាង៩៩៨៩នទី=៩ 17 380 118 101 234 209 Length (min) 110 96 170 125 119 105 106 120 113 92 149 108 81 157 94 90 154 132 150 97 117 96 106 127 94 127 140 124 150 108 132 136 136 116 119 Viewer Rating 6.7 2.2 7.6 8.0 7.4 5.8 4.8 7.7 8.3 5.7 6.5 8.6 1.9 7.8 5.8 2.0 7.8 8.4 7.5 2.7 6.0 6.3 7.0 6.6 2.0 7.8 8.0 6.4 8.5 6.6 5.3 6.8 8.1 6.7 7.3
