Statistics For Business And Economics 12th Edition By James T. McClave – Test Bank

CHAPTER 11—INFERENCES ABOUT POPULATION VARIANCES

MULTIPLE CHOICE

1. 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. -1.96 and 1.96
b. 32.357 and 71.420
c. 34.764 and 67.505
d. 12.8786 and 46.9630

ANS: B PTS: 1 TOP: Reading Chi-square

2. 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
b. Ho: s2  1.44
c. Ho:  < 1.20
d. Ho: 2  1.44

ANS: D PTS: 1 TOP: Hypothesis – Variance

3. 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. 100
b. 10
c. 51.25
d. 50

ANS: D PTS: 1 TOP: Inference – Variance

4. A sample of 21 observations yielded a sample variance of 16. If we want to test H0: 2 = 16, the test statistic is
a. 20
b. 21
c. 5
d. 50

ANS: A PTS: 1 TOP: Inference – Variance

5. The value of F.05 with 8 numerator and 19 denominator degrees of freedom is
a. 2.48
b. 2.58
c. 3.63
d. 2.96

ANS: A PTS: 1 TOP: Reading F

6. 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 size
b. the smaller sample size
c. the larger sample variance
d. the smaller sample variance

ANS: C PTS: 1 TOP: F Statistic

7. The symbol used for the variance of the population is
a. 
b. 2
c. S
d. S2

ANS: B PTS: 1 TOP: Variance

8. The symbol used for the variance of the sample is
a. 
b. 2
c. S
d. S2

ANS: D PTS: 1 TOP: Variance

9. The random variable for a chi-square distribution may assume
a. any value between -1 to 1
b. any value between – infinity to +infinity
c. any negative value
d. any value greater than zero

ANS: D PTS: 1 TOP: Chi-square Distribution

10. A sample of n observations is taken from a population. The appropriate chi-square distribution has
a. n degrees of freedom
b. n – 1 degrees of freedom
c. n – 2 degrees of freedom
d. n – 3 degrees of freedom

ANS: B PTS: 1 TOP: Chi-square Distribution