King Abdul Aziz University Department of Statistics
Assignment 7 (Chapter 17&18) Stat 271
Term 2, 2014
Name:______________________________
ID:_________________________________
Section:_____________________________
Marks Obtained:______________________
Please mark all your answers on the answer sheet
The due date Tuesday 7/7/1435
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1. --- is positively skewed, non-negative and based on degrees of freedom.
A) Chi-square distribution.
B) T distribution.
C) F distribution.
D) Both A and C.
2. What would you conclude, in the nonparametric goodness-of-fit test, if you failed to reject :There is no difference between the observed and expected frequencies.
A) There is a difference between the observed and the expected frequencies.
B) The differences between observed and the expected frequencies are not significant.
C) There is a difference between the observed and the observed frequencies.
D) The differences between the observed and the expected frequencies are significant.
3. A contingency table is made up of 4 rows and 3 columns. How many degrees of freedom are present?
A) 12 B) 9 C) 6 D) 5
4. A --- table is used to investigate whether two traits or characteristics are related A) frequency
B) ANOVA C) contingency D) none of the above
5. If the assumption of normality is violated for the dependent-t test, we can use the A) Kruskal-Wallis test.
B) Wilcoxon signed-rank test.
C) Wilcoxon rank-sum test.
D) Paired-t test.
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Answer the questions 6-10
Suppose as a market analyst you wished to see whether consumers have any preference among five flavors of new fruit soda. A sample of 100 people provided these data:
Flavor Frequency
Cherry 32
Strawberry 28
Orange 16
Lime 14
Grape 10
At 0.05 significance level, is there a preference in a selection of fruit soda flavors?
6. The null hypothesis and alternate hypothesis are:
A) : Consumers show a preference : Consumers show no preference
B) : There is a difference between the observed and expected frequencies.
: There is no difference between the observed and expected frequencies.
C) : There is no difference between the observed and expected frequencies.
: There is a difference between the observed and expected frequencies.
D) : The flavors are not equally distributed : The flavors are equally distributed
7. The expected value is:
A) 100 B) 20 C) 25 D) 5
8. The test statistics value of the test is:
A) 18 B) 4 C) 9.49 D) 0.0012
9. The critical value of test is:
A) 9.49 B) 11.07 C) 18 D) 4
3 10. The decision is:
A) Reject H0, there is no difference between the observed and expected frequencies.
B) Not reject H0, consumers show no preference C) Reject H0, The flavors are not equally distributed
D) Not reject H0, there is no difference between the observed and expected frequencies.
Questions (11-15) are based on the Wages data set on Data set folder Wages dataset represents information on annual wages of sample of 100 workers
Select the variable Industry (1= manufacturing, 2 = construction, 0 = others). At 0.01 significance level, are the workers equally distributed among the three industries?
11. The observed and expected frequency of construction workers?
A) 3, 33.33 B) 80, 33.33 C) 17, 33.33 D) 3, 100
12. The degrees of freedom of test is:
A) 3 B) 2 C) 100 D) 99
13. The decision is:
A) Not reject H0, there is a difference between the observed and expected frequencies.
B) Not reject H0, there is no difference between the observed and expected frequencies
C) Reject H0, there is a difference between the observed and expected frequencies.
D) Reject H0, there is no difference between the observed and expected frequencies.
Select the variables Occupation ( 1 = management, 2 = sales, 3 = clerical, 4 = service, 5 = professional, 0 = others) and Female ( 1 = yes, 0 = no). At 0.05 significance level, is there a relationship between two variables?
14. The critical value of test is:
A) 14.70 B) 9.49 C) 12.59 D) 11.07
4 15. The decision is:
A) Not Reject H0, there is a relationship between two variables.
B) Reject H0, there is no relationship between two variables.
C) Not Reject H0, there is no relationship between two variables.
D) Reject H0, there is a relationship between two variables.
Answer the questions 16-21 A survey shows this selection of snacks purchased. The result are shown.
Snack
Gender Hot dog Peanuts Popcorn
Women 12 15 19
Men 13 14 25
At = 0.1, is the snack chosen independent of gender of the consumer?
16. State the null hypothesis and the alternative hypothesis:
A) : There is a relationship between snack chosen and gender : There is no relationship between snack chosen and gender B) : There is no relationship between snack chosen and gender : There is a relationship between snack chosen and gender
C) : There is a relationship between the observed and expected frequencies.
: There is no relationship between the observed and expected frequencies.
D) : There is no relationship between the observed and expected frequencies.
: There is a relationship between the observed and expected frequencies.
17. The observed frequency of men who select popcorn:
A) 98 B) 44 C) 25 D) 23.35
18. The expected frequency of women who select hot dog:
A) 12 B) 11.73 C) 13 D) 13.27
19. The number of persons who select peanuts:
A) 29 B) 44 C) 25 D) 98
5 20. The value of the p-value of the test is:
A) 0.7682 B) 0.1 C) 0.53 D) 2
Answer the questions 22-25
A researcher wishes to compare the prices for prescription drugs in the United States with those in Canada.
The same drugs and dosages were compared in each country.
Drug United
States Canada
1 3.31 1.47
2 2.27 1.07
3 2.54 1.34
4 3.13 1.34
5 23.4 21.44
6 3.16 1.47
7 1.98 1.07
8 1.96 3.39
9 1.5 1.5
Assume the differences in prices do not follow a normal distribution. At = 0.1, can it be concluded that there is a difference in the prices in the two countries?
22. The test statistic is:
A) T = 32 B) T = 4 C) W = 109.5 D) W =61.5
23. The tabulated critical value is:
A) 3 B) 5 C) 0 D) 1
21. The decision of testing this claim is:
A) Not Reject H0, there is a relationship between snack chosen and gender B) Reject H0, there is no relationship between snack chosen and gender C) Not Reject H0, the snack chosen is independent of gender
D) Reject H0, the snack chosen is dependent of gender
6 24. The rank for the first drug is:
A) 1 B) 1.84 C) 7 D) 4
25. your decision is:
A) Reject H0,so we can conclude that there is a difference in the prices in the two countries
B) Not Reject H0, so we can conclude that that there is a difference in the prices in the two countries
C) Not Reject H0, so we can conclude that that there is no difference in the prices in the two countries
D) Reject H0, so we can conclude that that there is no difference in the prices in the two countries
Answer the questions 26-32
A random sample of men and women in prison was asked to give the length of sentence each received for a certain type of crime. The data (in months) are shown here.
Males Females
8 7
12 5
6 2
14 3
22 21
27 26
32 30
24 9
26 4
19 17
If the length of sentence are not normally distributed. At = 0.01, test the claim that there is no difference in the sentence received by each gender.
26. State the null hypothesis and the alternative hypothesis:
A) : There is a difference in the sentence received by each gender.
: There is no difference in the sentence received by each gender.
B) vs.
C) vs.
D) : There is no difference in the sentence received by each gender.
: There is a difference in the sentence received by each gender.
7 27. The suitable test is:
A) pooled variance t-test B) Wilcoxon signed rank test C) Wilcoxon rank sum test D) unequal variance t-test
28. Rank for the male who received 8 months:
A) 126.5 B) 8 C) 7 D) 1
29. W is equal to:
A) 83.5 B) 210 C) 126.5 D) 105
30. The test statistic is:
A) z = 1.625 B) W = 126.5 C) W = 83.5 D) t = 1.55
31. The critical values are:
A) ± 1.64 B) ± 2.58 C) ± 2.878 D) ± 1.96
32. The decision is:
A) Not Reject H0, There is no difference in the sentence received by each gender B) Not Reject H0, the average length of sentence of the two groups are equal C) Reject H0, There is a difference in the sentence received by each gender D) Reject H0, the average length of sentence of the two groups are not equal.
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Answer the questions 33-38
A nutritionist wishes to compare the number of carbohydrates in one serving of three low-carbohydrates foods.
Pasta Ice cream Bread
11 5 43
22 13 62
16 10 71
29 8 49
25 12 50
25 11 80
75 At = 0.1, is there a difference in the number of calories?
33. The alternative hypothesis is:
A) The population distribution of the number of calories for the three foods are the same
B) The mean of calories for the three foods are the same
C) The population distribution of the number of calories for the three foods are not the same
D) The mean of calories for the three foods are not the same
34. Sum of ranks for the Ice cream is equal to:
A) 54.5 B) 23.5 C) 112 D) 3.92
35. The test statistic is:
A) F = 15.129 B) F = 51.34 C) H = 15.129 D) H = 4.61
36. The critical values are:
A) H = 15.129 B) = 4.61 C) F = 2.67 D) = 6.25
9 37. The p-value of the test is:
A) 1.09E-07 B) 0.0005 C) 0.1 D) 0.05
38. The decision is:
A) Not Reject H0, the population distribution of the number of calories for the three foods are the same
B) Not Reject H0, the mean of calories for the three foods are the same C) Reject H0, the mean of calories for the three foods are not the same
D) Reject H0, the population distribution of the number of calories for the three foods are not the same
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