A manufacturing plant has preliminary contracts with three

The survey of Chase and Dummer (1992) discussed in Exercise 1 of Sec. 10.3 was actually collected by sampling from three subpopulations according to the locations of the schools: rural, suburban, and urban. Table 10.24 shows the responses to the survey question classified by school location. Test the null hypothesis that the distribution of responses is the same in all three types of school location. Table 10.24 Data for Exercise 1 from Chase and Dummer (1992) Good Athletic grades ability Popularity Rural 57 42 50 Suburban 87 22 42 Urban 103 2

An examination was given to 500 high school seniors in each of two large cities, and their grades were recorded as low, medium, or high. The results are given in Table 10.25. Test the hypothesis that the distributions of scores among seniors in the two cities are the same. Table 10.25 Data for Exercise 2 Low Medium High City A 103 145 252 City B 140 136 224

Every Tuesday afternoon during the school year, a certain university brought in a visiting speaker to present a lecture on some topic of current interest. On the day after the fourth lecture of the year, random samples of 70 freshmen, 70 sophomores, 60 juniors, and 50 seniors were selected from the student body at the university, and each of these students was asked how many of the four lectures she had attended. The results are given in Table 10.26. Test the hypothesis that freshmen, sophomores, juniors, and seniors at the university attended the lectures with equal frequency. Table 10.26 Data for Exercise 3 Number of lectures attended 01234 Freshmen 10 16 27 6 11 Sophomores 14 19 20 4 13 Juniors 15 15 17 4 9 Seniors 19 8 6 5

Suppose that five persons shoot at a target. Suppose also that for i = 1,..., 5, person i shoots ni times and hits the target yi times, and that the values of ni and yi are as given in Table 10.27. Test the hypothesis that the five persons are equally good marksmen. Table 10.27 Data for Exercise 4 i ni yi 1 17 8 2 16 4 3 10 7 4 24 13 5 16 10

A manufacturing plant has preliminary contracts with three different suppliers of machines. Each supplier delivered 15 machines, which were used in the plant for four months in preliminary production. It turned out that one of the machines from supplier 1 was defective, seven of the machines from supplier 2 were defective, and seven of the machines from supplier 3 were defective. The plant statistician decided to test the null hypothesis H0 that the three suppliers provided the same quality. Therefore, he set up Table 10.28 and carried out a 2 test. By summing the values in the bottom row of Table 10.28, he found that the value of the 2 statistic was 24/5 with two degrees of freedom. He then found from a table of the 2 distribution that H0 should be accepted when the level of significance is 0.05. Criticize this procedure and provide a meaningful analysis of the observed data. Table 10.28 Data for Exercise 5 Supplier 1 23 Number of defectives Ni 1 77 Expected number of defe

Suppose that 100 students in a physical education class shoot at a target with a bow and arrow, and 27 students hit the target. These 100 students are then given a demonstration on the proper technique for shooting with the bow and arrow. After the demonstration, they again shoot at the target. This time 35 students hit the target. What additional information, if any, is needed in order to investigate the hypothesis that the demonstration was helpful?

As people entered a certain meeting, n persons were selected at random, and each was asked either to name one of two political candidates she favored in a forthcoming election or to say undecided if she had no real preference. During the meeting, the people heard a speech on behalf of one of the candidates. After the meeting, each of the same n persons was again asked to express her opinion. Describe a method for evaluating the effectiveness of the speaker