1. A random sample of 31 charge sales showed a sample standard deviation of $50. A 90% confidence interval estimate of the population standard deviation is A. 41.39 to 63.68
2. A sample of 20 cans of tomato juice showed a standard deviation of 0.4 ounces. A 95% confidence interval estimate of the variance for the population is A. 0.0925 to 0.3413
3. A sample of 21 elements is selected to estimate a 90% confidence interval for the variance of the population. The chi-square value(s) to be used for this interval estimation is (are)
a. -1.96 and 1.96 A. 12.443 and 28.412
4. A sample of 41 observations yielded a sample standard deviation of 5. If we want to test H0: 2 = 20, the test statistic is A. 50
5. A sample of 51 elements is selected to estimate a 95% confidence interval for the variance of the population. The chi-square values to be used for this interval estimation are A. 32.357 and 71.420
6. A sample of 60 items from population 1 has a sample variance of 8 while a sample of 40 items from population 2 has a sample variance of 10. If we test whether the variances of the two populations are equal, the test statistic will have a value of A. 1.25
7. A sample of 61 observations yielded a sample standard deviation of 6. If we want to test
Ho: 2 = 40, the test statistic is A. 54
8. A sample of n observations is taken from a population. The appropriate chi-square distribution has A. n – 1 degrees of freedom
9. For an F distribution, the number of degrees of freedom for the numerator A. can be larger, smaller, or equal to the number of degrees of freedom for the denominator
10. The 90% confidence interval estimate for a population standard deviation when a sample variance of 50 is obtained from a sample of 15 items is A. 5.44 to 10.32
11. The 95% confidence interval estimate for a population variance when a sample variance of 324 is obtained from a sample of 81 items is A. 243.087 to 453.518
12. The 99% confidence interval estimate for a population variance when a sample standard deviation of 12 is obtained from a sample of 10 items is A. 54.94 to 747.01
13. The bottler of a certain soft drink claims their equipment to be accurate and that the variance of all filled bottles is 0.05 or less. The null hypothesis in a test to confirm the claim would be written as A. H0: 2 0.05
14. The chi-square value for a one-tailed (upper tail) hypothesis test at 95% confidence and a sample size of 25 is A. 36.415
15. The chi-square value for a one-tailed test (lower tail) when the level of significance is 0.1 and the sample size is 15 is A. 7.785
16. The chi-square values (for interval estimation) for a sample size of 10 at 95% confidence are A. 2.700 and 19.023
17. The critical value of F at 95% confidence when there is a sample size of 21 for the sample with the smaller variance, and there is a sample size of 9 for the sample with the larger sample variance is A. 2.45
18. The manager of the service department of a local car dealership has noted that the service times of a sample of 15 new automobiles has a standard deviation of 4 minutes. A 95% confidence interval estimate for the variance of service times for all their new automobiles is A. 8.576 to 39.796
19. The manager of the service department of a local car dealership has noted that the service times of a sample of 30 new automobiles has a standard deviation of 6 minutes. A 95% confidence interval estimate for the standard deviation of the service times for all their new automobiles is A. 4.778 to 8.066
20. The producer of a certain bottling equipment claims that the variance of all their filled bottles is 0.027 or less. A sample of 30 bottles showed a standard deviation of 0.2. The p-value for the test is A. between 0.025 to 0.05
21. The producer of a certain medicine claims that their bottling equipment is very accurate and that the standard deviation of all their filled bottles is 0.1 ounce or less. A sample of 20 bottles showed a standard deviation of 0.11. The test statistic to test the claim is A. 22.99
22. The random variable for a chi-square distribution may assume A. any value greater than zero
23. The sampling distribution of the quantity (n-1)s/is the A. chi-square distribution
24. The sampling distribution of the ratio of independent sample variances extracted from two normal populations with equal variances is the A. Z distribution
25. The sampling distribution of the ratio of two independent sample variances taken from normal populations with equal variances is A. an F distribution
26. The sampling distribution used when making inferences about a single population’s variance is A. a chi-square distribution
27. The symbol used for the variance of the population is A. 2
28. The symbol used for the variance of the sample is A. S2
29. The value of F.05 with 8 numerator and 19 denominator degrees of freedom is A. 2.48
30. The value of F0.01 with 9 numerator and 20 denominator degrees of freedom is A. 3.46
31. To avoid the problem of not having access to Tables of F distribution with values given for the lower tail, the numerator of the test statistic should be the one with A. the larger sample variance
32. To avoid the problem of not having access to tables of the F distribution with values given for the lower tail when a two-tailed test is required, let the smaller sample variance be A. the denominator of the test statistic
33. We are interested in testing to see if the variance of a population is less than 7. The correct null hypothesis is A. 2 7
34. We are interested in testing whether the variance of a population is significantly more than 625. The null hypothesis for this test is A. Ho: 2 < 25
35. We are interested in testing whether the variance of a population is significantly less than 1.44. The null hypothesis for this test is A. Ho: 2 1.44
36. Which of the following has a chi-square distribution? A. (n – 1)S2/2
37. Which of the following has an F distribution? A. S(2/1)/S(2/2)
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