# pexam4S06 - STT 201 UNIT 4 Example Multiple Choice...

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STT 201 UNIT 4 Example Multiple Choice Questions 1-4. For each of the following testing situations, give the p-value of the observed test statistic. Pick the closest . 1. Two-sample t-test of H 0 : μ 1 - μ 2 0 versus H a : μ 1 - μ 2 < 0, sample sizes n 1 = 12, n 2 = 10, t obs = 1.38. Adopt the conservative approach to the degrees of freedom. (a) .10 (b) .05 (c) .20 (d) .50 (e) .90 2. Two-sample (large samples) z-test of H 0 : π 1 - π 2 0 v. H a : π 1 - π 2 > 0 if p 1 = .47, p 2 = .33 and z obs = 1.15. (a) .085 (b) .071 (c) .054 (d) .125 (e) .101 3. A categorical variable y has five levels. Two populations are tested for having the same distribution of y using large samples drawn from each population and χ 2 obs = 11.12. (a) .085 (b) .071 (c) .054 (d) .025 (e) .037 4. A categorical variable y has three levels. Four populations are tested for having the same distribution of y using large samples drawn from each population and χ 2 obs = 2.20. (a) .085 (b) .001 (c) .050 (d) .900 (e) .100 5-6. A researcher administered a reading comprehension test to each of 16 subjects before and after a special course that each subject took to improve reading comprehension. The researcher set the hypotheses H 0 : μ d 0 and H a : μ d > 0 where d denotes difference (improvement). The summary of the data is given below. Descriptive Statistics N Mean Standard deviation Before 16 52.8 9.3 After 16 56.8 8.1 Difference 16 4.0 7.6 5. What is the value of t obs for testing H 0 ? (a) 2.11 (b) 7.6 (c) 0.45 (d) 2.00 (e) 4.0 6. What is the p-value of t obs ? (a) .10 (b) .05 (c) .025 (d) .01 (e) .005 7-12. A veterinarian believes that the rate of hip dysplasia in Boxers (breed of dog) is less than the rate hip dysplasia in American Bulldogs (breed of dog) and decides to test the hypothesis H 0 : π 1 - π 2 0 v. H a : π 1 - π 2 < 0. A random sample of 80 Boxers has 8 dogs with hip dysplasia. A random sample of 140 American Bulldogs has 21 dogs with hip dysplasia. 7. What is the standard error of the estimate p 1 – p 2 used in calculating the CI for π 1 - π 2 ? (a) .085 (b) .071 (c) .045 (d) .037 (e) .101 8. What is the 99% CI estimate of the difference in population rates π 1 - π 2 ? (a) -.05 ± .12 (b) -.05 ± .07 (c) -.05 ± .09 (d) -.05 ± .20 (e) -.05 ± .17 9. What is the standard error of the estimate p 1 – p 2 used in calculating the z-test statistic ? ( Hint: This is the denominator of z-test statistic. ) (a) .085 (b) .071 (c) .064 (d) .047 (e) .101 10. Compute the value z obs of the z-test statistic. (a) 0.52 (b) -0.90 (c) 1.96 (d) –1.06 (e) -1.96 11. What is the p-value of the test statistic z obs that is appropriate for this test? Pick the closest. (a) 0.30 (b) 0.18 (c) 0.14 (d) 0.05 (e) 0.025 12. What decision is reached at 2% level of significance? (a) reject the null hypothesis (b) retain the null hypothesis

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13-15. A study is undertaken to compare the distributions of weights of adult perch in Lake Michigan, Lake Huron and Lake Erie. Random samples of sizes 100, 200, 300 respectively are obtained from these lakes and each sample fish is weighed. Weight is recorded in four categories. The sample data are shown below.
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## This note was uploaded on 09/27/2010 for the course STT STT 201 taught by Professor Sinnott during the Summer '10 term at Michigan State University.

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pexam4S06 - STT 201 UNIT 4 Example Multiple Choice...

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