1. A recent national survey asked adults if they thought the government should continue to fund NASA's efforts to send un-manned missions to Mars. 55% said they should, 40% said they should not, and 5% had no opinion. A sample of 200 college students resulted in the numbers below. At "alpha" = 0.05, can we conclude that opinions of college students differ from those in the national survey of adults?
Response Should Should Not No Opinion
Number 125 70 5
2. A national survey claims that people buy music compact disks in equal percentages for the following five age groups: 14 -18, 19 - 23, 24 - 28, 29 - 33, and over 33. A sample of the ages of 100 CD buyer's at Hastings, on Fry Blvd, gave these data: 15, 21, 18, 30, and 16, for the sequence of age groupings, respectively. At "alpha" = 0.01 can we conclude that the local numbers are the same as the national survey?
3. A researcher wishes to try three different techniques to lower blood pressure. Subjects are randomly assigned to three groups, as indicated in the table below. After four weeks, the reduction in each person's blood pressure is recorded. At "alpha" = 0.05, use ANOVA to test the claim that there is no difference among the means. If the null hypothesis is rejected, do NOT do the follow-up test to determine where differences may occur.
Medication Exercise Diet
10 11 10
12 10 13
14 9 15
12 11 15
12 13 16
4. Given that the null hypothesis was rejected in an ANOVA test, determine where there are significant differences among the means, if the ANOVA test had a C.V. = 2.71 at alpha = .05, N1 = N2 = N3 = 6 (sample sizes), Sw2 = 600, and X'1 = 200, X'2 = 175 X'3 = 100 . Use the appropriate test.
5. Given that the null hypothesis was rejected in an ANOVA test, determine where there are significant differences among the means, if the ANOVA test had a C.V. = 5.93 at alpha = .01, N1 = 6, N2 = 6, N3 = 8 (sample sizes), Sw2 = 800, and X'1 = 230, X'2 = 200 X'3 = 155. Use the appropriate test.
6. A store owner feels that the median number of snow cones sold per day is 39. A random sample of 20 days shows the following data. At "alpha" = 0.01 is there enough evidence to reject the claim?
18 43 40 16 22
30 29 32 37 40
39 34 39 45 40
36 40 34 39 52
7. Is there enough evidence to support the hypothesis that fewer than 65% of students favor single-room dorms if 16 of 50 students favored single-room dorms, at "alpha" = .01?
8. Two different lab machines measure the sodium content (in milligrams) of the same 10 blood samples (below.) At "alpha" = 0.01, test the claim that both gave the same readings.
9. To test the claim that there is no difference in the lifetimes (in months) of two brands of video games, a sample of each was selected as indicated in the table. At "alpha" = 0.01, can we conclude that there is a difference?
Use the Wilcoxon rank sum test. (9 points: 2,2,3,1,1)
Brand A 42 34 39 42 22 47 51 34 41 39 28
Brand B 29 39 38 43 45 49 53 38 44 43 32
22 28 29 32 34 34 38 38 39 39 39 41 42 42 43 43 44 45 47 49 51 53
A A B B A A B B A B A A A A B B B B A B A B
1 2 3 4 5.5 7.5 10 10 10 12 13.5 15.5 17 18 19 20 21 22
10. A sample of legal costs (in thousands of dollars) for school districts for two recent consecutive years is shown. At alpha = .05, is there a difference in the costs? Use wilcoxon signed-rank
11. A recent study examined the number of unemployed people in 5 cities who are actively seeking employment. AT alpha = .05, is there a difference in the number based on level of education earned?
