Questions 13.6 and 13.8 are to be answered only
Assignment 4 Do 13.6, 13.8 v14 In random samples of 12 from each of two normal populations, we found the following statistics: 31:74 51=18 i2=71 52:16 Developing an Understanding of Statistical Concepts Ext-mite; 13.513.10 are 'tvbat-ff\" analyses designed to deter- mine what bappm to the tart Militia and interval estimate: when elements oftbe statistical inference change. These problems can it: solved my, using the Excel Jprrdtbeett you mated ' _ a. Test with a = .05 to determine whether we can or Mmrtab. infer that the population means dier. 13.5 In random samples of 25 from each of two normal b\" Repeat part (a) increasing the standard devia populations, we found the following statistics: 91 = 524 31 = 129 :2 = 469 52 = 141 a. Estimate the difference between the two popula- tion means with 95 96 condence. b. Repeat part (3) increasing the standard deviations to :1: 255 and :2 = 260. c. Describe what happens when the sample stan dard deviations get larger. tions to :1: 210 and :2 = 198. c. Describe what happens when the sample stan- dard deviations get larger. d. Repeat part (a) with samples of size 150. e. Discuss the effects of increasing the sample size. f. Repeat part (a) changing the mean of sample 1 to .i'. = 76. g. Discuss the effect of increasing 3:" . 13.7 Random sampling from two normal populations produced the following results: (1. Repeat part (a) with samples ofsize 100. R1 = 63 51 = 18 "I = 50 e. Discuss the effects ofincreasing the sample size. it2 = 60 52 = 7 h2 = 45 ' 15.12 NW" A mens softball league IS expenmennng \\A Random sampling from two normal populations produced the following results: 21:412 51:123 x2=405 52:54 n,=150 n2=150 a. Can we infer at the 5% signicance level that a, is greater than 142? b. Repeat part (a) decreasing the standard devia- tions to :1 = 31 and :2 :16. c. Describe what happens when the sample stan- dard deviations get smaller. d. Repeat part (a) with samples of size 20. e. Discuss the effects of decreasing the sample size. f. Repeat part (a) changing the mean of sample 1 to 5:. = 409 g. Discuss the effect of decreasing i1. 13.13 with a yellow baseball that is easier to see during night games. One way to judge the e'ectiveness is to count the number of errors. In a preliminary experiment. the yellow baseball was used in 10 games and the tradi- tional white baseball was used in another 10 games. The number of errors in each game was recorded and is listed here. Can we infer that there are fewer errors on average when the yellow ball is used? Yellow5267253849 White768591183610 "" 3'13 A number of restaurants feature a device that allows credit card users to swipe their cards at the table. It allows the user to specify a percentage or a dollar amount to leave as a tip. In an experiment to see how it works. a random sample of credit card nce-nonv- u-m- alumna Cum nah-l ulna "mud .mu. .wu-l ham
