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Chapter 9 Practice Test A Name: __________________________ Date: _____________ Use the following to answer questions 1-2: A sociologist wants to determine if the life expectancy of people in Africa is less than the life expectancy of people in Asia. The data obtained is shown in the table below. Africa Asia X 55.3 65.2 8.1 9.3 n 53 42 1. What is the null hypothesis? Use 0.05 . A) H0 : 1 2 B) H0 : 1 2 C) H0 : 1 2 D) H0 : 1 2 2. Calculate the critical value. Use 0.05 . A) –1.96 B) –2.58 C) –1.65 D) –2.33 3. When testing the difference between two proportions, one sample had 30 out of 100 who were for capital punishment and the other sample had 60 out of 80 who were for capital punishment. Calculate the standard error. A) 0.060 B) 0.042 C) 0.098 D) 0.075 4. Determine the 95% confidence interval of the true difference in the means. A sociologist wants to determine if the life expectancy of people in Africa is less than the life expectancy of people in Asia. The data obtained is shown in the table below. Use 0.05 . Africa Asia X 55.3 65.2 8.1 9.3 n 53 42 A) 16.33 1 2 5.98 C) 13.46 1 2 6.34 B) 1216 1 2 6.86 . D) 1135 1 2 7.58 . Page 1 Chapter 9 Practice Test A 5. The campus bookstore asked a random set of freshmen and seniors as to how much they spent on textbooks in that term. The bookstore believes that the two groups spend the same amount. What is the test value? Freshmen Seniors Sample size 70 40 Mean spending 40 45 Sample variance 400 700 A) –1.04 B) –1.75 C) 4.82 D) –0.22 6. If s1 12.31 and F 2.13 , what is the value of s2 as shown in the figure below? A) 8.43 B) 17.97 C) 5.78 D) 71.14 7. A car salesman claims that the variance of prices on convertibles is higher than the variance on station wagons. The standard deviation of 16 convertibles is $6800 and the standard deviation of 24 station wagons is $3900. For 0.05 , what is the test value? A) 3.04 B) 2.78 C) 2.33 D) 3.00 8. A recent survey reported that in a sample of 300 students who attend two-year colleges, 105 work at least 20 hours a week. In a sample of 225 students attending private universities, only 20 students work at least 20 hours per week. What is the test value? A) 7.61 B) 2.38 C) 4.18 D) 6.95 9. What is the critical value for a two-tailed F -test with 010 , when the sample size . from which the variance for the numerator was obtained was 10, and the sample size from which the denominator was obtained was 24? A) 2.25 B) 2.32 C) 2.30 D) 2.27 Page 2 Chapter 9 Practice Test A Use the following to answer question 10: Mauricio Cruz, a wine merchant for Cruz's Spirits Emporium, wants to determine if the average price of imported wine is less than the average price of domestic wine. The data obtained is shown in the table below. Imported Wine Domestic Wine X 7.03 9.78 s 2.31 3.62 n 15 16 10. What is the critical value? Use 0.05 . A) –1.703 B) –1.761 C) –2.045 D) –1.697 11. Many elementary school students in a school district currently have ear infections. A random sample of children in two different schools found that 15 of 46 at one school and 21 of 38 at the other had this infection. At the .05 level of significance, is there sufficient evidence to conclude that a difference exists between the proportion of students who have ear infections at one school and the other? A) Yes, there is sufficient information to reject the hypothesis that the proportions of students at the two schools who have ear infections are the same because the test value –10.67 is outside the acceptance region (-1.96,1.96). B) Yes, there is sufficient information to reject the hypothesis that the proportions of students at the two schools who have ear infections are the same because the test value –19.25 is outside the acceptance region (-1.96,1.96). C) Yes, there is sufficient information to reject the hypothesis that the proportions of students at the two schools who have ear infections are the same because the test value –2.09 is outside the acceptance region (-1.96,1.96). D) Yes, there is sufficient information to reject the hypothesis that the proportions of students at the two schools who have ear infections are the same because the test value –2.74 is outside the acceptance region (-1.96,1.96). Page 3 Chapter 9 Practice Test A 12. A pharmaceutical company is testing the effectiveness of a new drug for lowering cholesterol. As part of this trial, they wish to determine whether there is a difference between the effectivess for women and for men. At α = .05, what is the test value? Women Men Sample size 40 60 Mean effect 7.5 7.05 Sample variance 3 5 A) 1.13 B) 2.84 C) 0.40 D) 0.88 13. Determine the value of as shown in the figure below, if the degrees of freedom were seven and nine. A) 0.025 B) 0.05 C) 0.1 D) 0.01 14. If the test value in the figure below, for a test of the difference between two large sample means, is 2.57 when the critical value is 1.96, what decision about the hypothesis should be made? A) reject the alternative hypothesis C) not enough information B) reject the null hypothesis D) accept the null hypothesis Page 4 Chapter 9 Practice Test A 15. In comparing the two standard deviations below, what is the test value and what are the degrees of freedom that should be used? Standard Deviation Number of values Sample 1 5 18 Sample 2 3 26 A) test value = 1.67, degrees of freedom = 17 and 25 B) test value = 2.78, degrees of freedom = 18 and 26 C) test value = 2.78, degrees of freedom = 17 and 25 D) test value = 1.67, degrees of freedom = 18 and 26 16. A running coach wanted to see whether runners ran faster after eating spaghetti the night before. 20 random runners were chosen for this study. They ran a 5 kilometer race after having a normal dinner the night before, and then a week later, reran the same race after having a spaghetti dinner the night before. Their results (in seconds) are in the table below. At α = .01, what is the test value to use for this test? Regular Dinner Spaghetti Difference Dinner by runner Sample mean 1100 1085 –15 Sample variance 2200 2200 500 A) –3.00 B) –3.72 C) –0.67 D) –0.23 17. Find p and q when X 1 =16, n1 =60, X 2 =25, and n2 =60 A) p = 2.93 and q = 1.52 C) p = 0.66 and q = 0.34 B) p = 1.52 and q = 2.93 D) p = 0.34 and q = 0.66 Page 5 Chapter 9 Practice Test A Use the following to answer questions 18-20: A researcher wanted to determine if using an octane booster would increase gasoline mileage. A random sample of seven cars was selected; the cars were driven for two weeks without the booster and two weeks with the booster. Miles / Gal Without Miles / Gal With 21.2 23.8 25.4 25.6 20.9 22.4 27.6 28.3 22.8 24.5 27.3 28.8 23.4 25.2 18. State the alternative hypothesis? A) H1: D 0 B) H1: D 0 C) H1: D 0 D) H1: D 0 19. What is the critical value using 0.05 ? A) -1.895 B) -1.943 C) -1.782 D) -1.761 20. Determine the mean of the difference. A) –1.43 B) 1.43 C) –0.96 D) –6.3 Page 6 Chapter 9 Practice Test A Answer Key 1. A 2. C 3. D 4. C 5. A 6. A 7. A 8. D 9. B 10. B 11. C 12. A 13. A 14. B 15. B 16. A 17. D 18. D 19. B 20. A Page 7

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