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Unformatted text preview: CHAPTER 12 SECTION 2: INFERENCE ABOUT A POPULATION MULTIPLE CHOICE 50. A random sample of 25 observations is selected from a normally distributed population. The sample variance is 10. In the 95% confidence interval for the population variance, the upper limit is: a. 17.110 b. 6.097 c. 17.331 d. 19.353 ANS: D PTS: 1 REF: SECTION 12.2 51. In a hypothesis test for the population variance, the hypotheses are H : 2 = 30 vs. H 1 : 2 < 30. If the sample size is 20 and the test is being carried out at the 5% level of significance, the null hypothesis is rejected if: a. 2 < 30.144. b. 2 > 10.851. c. 2 < 10.117. d. 2 > 31.410. ANS: C PTS: 1 REF: SECTION 12.2 52. In a hypothesis test for the population variance, the hypotheses are H : 2 = 100 vs. H 1 : 2 100. If the sample size is 15 and the test is being carried out at the 10% level of significance, the rejection region is: a. 2 < 6.571 or 2 > 23.685. b. 2 < 7.790 or 2 > 21.064. c. 2 < 8.547 or 2 > 22.307. d. 2 < 7.261 or 2 < 24.996. ANS: A PTS: 1 REF: SECTION 12.2 53. The statistic ( n- 1) s 2 / 2 has a chi-squared distribution with n - 1 degrees of freedom if: a. the population is normally distributed with variance equal to 2 . b. the sample is normally distributed with variance equal to s 2 . c. the sample has a Student t-distribution with degrees of freedom equal to n - 1. d. All of these choices are true. ANS: A PTS: 1 REF: SECTION 12.2 54. Which of the following is not an example illustrating the use of variance? a. As a measure of risk. b. As a judge of consistency. c. To search for and reduce variability in a process. d. All of these choices are true. ANS: D PTS: 1 REF: SECTION 12.2 This edition is intended for use outside of the U.S. only, with content that may be different from the U.S. Edition. This may not be resold, copied, or distributed without the prior consent of the publisher. 55. Which of the following conditions is needed regarding the chi-squared test statistic for the test of variance? a. The population random variable must be normal....
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This note was uploaded on 11/02/2011 for the course STAT 1001 taught by Professor Kim during the Spring '11 term at Yonsei University.
- Spring '11