Chapter 11 Pages 351-352, Questions 24, 34, 37, and 38 Question #24 Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the night shift than on the day shift. Assume the population standard deviation for the number of units produced on the day shift is 21 and 28 on the night shift. A sample of 54-dayshift workers showed that the mean number of units produced was 345. A sample of 60 night-shift workers showed that the mean number of units produced was 351. At the .05 significance level, is the number of units produced on the night shift larger? Question #34 A study was conducted to determine if there was a difference in the humor content in British and American trade magazine advertisements. In and independent random sample of 270 American trade magazine advertisement, 56 were humorous. And independent random sample of 203 British trade magazines contained 52 humorous ads. Does this data provide evidence at the .05 significance level that there is a difference in the proportion of humorous ads in British versus American trade magazines? Question #37 The manufacturer of an MP3 player wanted to know whether a 10% reduction in price is enough to increase the sales of its product. To investigate, the owner randomly selected eight outlets and sold the MP3 player at the reduced price. At seven randomly selected outlets, the MP3 player was sold at the regular price. Reported below is the number of units sold last month at the sampled outlets. At the .01 significance level, can the manufacturer conclude that the price reduction resulted in an increase in sales? Regular Price Reduced price 138 121 88 115 141 125 96 128 134 152 135 114 106 112 120 Question #38 A number of minor automobile accidents occur at various high-risk intersections in Teton County despite traffic lights. The Traffic Department claims that a modification in the type of light will reduce these accidents. The county commissioners have agreed to a proposed experiment. Eight intersections were chosen at random, and the lights at those intersections were modified. The numbers of minor accidents during a six-month period before and after the modifications were: Before modification After modification A 5 B 7 Number of Accidents C D E 6 4 8 3 7 7 0 4 F 9 G 8 H 10 6 8 2 At the .01 significance level, is it reasonable to conclude that the modification reduced the number of traffic accidents