ODD ANSWERS A91 17. (a) H0: s1 = s2 (claim); Ha: s1 ≠ s2 (b) F0 = 1.81; Rejection region: F 7 1.81 (c) 1.900 (d) Reject H0. (e) There is enough evidence at the 10% level of significance to reject the claim that the standard deviations of hotel room rates in Sacramento, CA, and San Francisco, CA, are the same. 19. (a) H0: s 2 1 = s 2 2 Ha: s 2 1 ≠ s 2 2 (claim) (b) F0 = 5.32; Rejection region: F 7 5.32 (c) 1.37 (d) Fail to reject H0. (e) There is not enough evidence at the 1% level of significance to support the claim that the test score variance for reading and writing is different from that for math. 21. (a) H0: m1 = m2 = m3 = m4 Ha: At least one mean is different from the others. (claim) (b) F0 = 2.26; Rejection region: F 7 2.26 (c) 2.18 (d) Fail to reject H0. (e) There is not enough evidence at the 10% level of significance to conclude that at least one monthly electric bill is different from the others. Quiz for Chapter 10 (page 576) 1. (a) H0: The distribution of educational attainment for people in the United States ages 30 –34 is 3.5% none–8th grade, 5.5% 9th–11th grade, 27.6% high school graduates, 15.2% some college, no degree, 10.6% associate’s degree, 23.4% bachelor’s degree, 10.6% master’s degree, and 3.6% professional/doctoral degree. Ha: The distribution of educational attainment for people in the United States ages 30–34 differs from the distribution for people ages 25 and older. (claim) (b) x2 0 = 14.067; Rejection region: x 2 7 14.067 (c) 3.958 (d) Fail to reject H0. (e) There is not enough evidence at the 5% level of significance to conclude that the distribution for people in the United States ages 30–34 differs from the distribution for people ages 25 and older. 2. (a) H0: Age and educational attainment are independent. Ha: Age and educational attainment are dependent. (claim) (b) x2 0 = 18.475; Rejection region: x 2 7 18.475 (c) 8.187 (d) Fail to reject H0. (e) There is not enough evidence at the 1% level of significance to conclude that educational attainment is dependent on age. 3. (a) H0: s 2 1 = s 2 2 Ha: s 2 1 ≠ s 2 2 (claim) (b) F0 = 4.43; Rejection region: F 7 4.43 (c) 1.38 (d) Fail to reject H0. (e) There is not enough evidence at the 1% level of significance to conclude that the variances in annual wages for Ithaca, NY, and Little Rock, AR, are different. 4. (a) H0: m1 = m2 = m3 (claim) Ha: At least one mean is different from the others. (b) F0 = 2.44; Rejection region: F 7 2.44 (c) 15.02 (d) Reject H0. (e) There is enough evidence at the 10% level of significance to reject the claim that the mean annual wages are the same for all three cities. Real Statistics—Real Decisions for Chapter 10 (page 578) 1. Fail to reject H0. There is not enough evidence at the 1% level of significance to conclude that the distribution of responses differs from the expected distribution. 2. (a) E1, 1 = 15, E1, 2 = 120, E1, 3 = 165, E1, 4 = 185, E1, 5 = 135, E1, 6 = 115, E1, 7 = 155, E1, 8 = 110, E2, 1 = 15, E2, 2 = 120, E2, 3 = 165, E2, 4 = 185, E2, 5 = 135, E2, 6 = 115, E2, 7 = 155, E2, 8 = 110 (b) There is enough evidence at the 1% level of significance to conclude that the ages of the victims are related to the type of fraud. Cumulative Review for Chapters 9 and 10 (page 580) 1. (a) x y 9.2 9.6 10.0 10.4 10.8 10.4 10.6 10.8 11.0 11.2 11.4 11.6 11.8 12.0 Men’s times (in seconds) Women’s times (in seconds) r ≈ 0.774; strong positive linear correlation (b) There is enough evidence at the 5% level of significance to conclude that there is a significant linear correlation between the men’s and women’s 100-meter times. (c) y = 1.2283x - 1.2253 x y 9.2 9.6 10.0 10.4 10.8 10.4 10.6 10.8 11.0 11.2 11.4 11.6 11.8 12.0 Men’s times (in seconds) Women’s times (in seconds) (d) 10.93 2. There is enough evidence at the 10% level of significance to reject the claim that the mean expenditures are the same for all four regions. 3. (a) 12,426 pounds per acre (b) 12,201 pounds per acre
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