Quiz 8 Flashcards
(25 cards)
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. 1,715 to 4,055.68
b. 1,596 to 4,466.73
c. 41.39 to 63.68
d. 39.96 to 66.83
c. 41.39 to 63.68
A saple 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. 0.2313 to 0.8533
b. 0.2224 to 0.7924
c. 0.0925 to 0.3413
d. 0.0889 to 0.3169
c. 0.0925 to 0.3413
A sample of 28 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. 16.151 and 40.113
b. 14.573 and 43.195
c. 15.308 and 44.461
d. -1.96 and 1.96
b. 14.573 and 43.195
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 12. If we test whether the variances of the two populations are equal, the test statistic will have a value of
a. 1.56
b. 1.25
c. 0.8
d. 1.5
d. 1.5
n = 81. s^2= 625. H0: o^2 = 500
Ha: o^2 not equal 500
The p-value is between
a. 0.025 and 0.05
b. 0.2 and 0.3
c. 0.05 and 0.1
d. 0.1 and 0.2
d. 0.1 and 0.2
n = 81. s^2= 625. H0: o^2 = 500
Ha: o^2 not equal 500
At 95% confidence, the null hypothesis
a. None of these alternatives is correct
b. should be revised
c. should not be rejected
d. should be rejected
c. should not be rejected
The contents of a sample of 26 cans of apple juice showed a standard deviation of 0.06 ounces. We are interested in testing to determine whether the variance of the population is significantly more than 0.003
The test statistic is
a. 30
b. 500
c. 1.2
d. 31.2
a. 30
The contents of a sample of 26 cans of apple juice showed a standard deviation of 0.06 ounces. We are interested in testing to determine whether the variance of the population is significantly more than 0.003
At 95% confidence, the critical value(s) from the table is(are)
a. 37.6525
b. 14.6114 and 37.6525
c. 13.1197 and 40.6465
d. 14.6114
a. 37.6525
n = 30. H0: o^2 = 500
s^2 = 625 Ha: o^2 not equal to 500
The null hypothesis is to tested at the 5% level of significance. The critical value(s) from the table is(are)
a. 16.0471 and 45.7222
b. 16.7908 and 46.9792
c. 43.7729
d. 42.5569
a. 16.0471 and 45.7222
n = 30. H0: o^2 = 500
s^2 = 625 Ha: o^2 not equal to 500
The null hypothesis
a. should not be rejected
b. should be revised
c. should be rejected
d. None of these alternatives are correct
a. should not be rejected
s^2 32. 38
n. 24. 16
We want to test the hypothesis that the population variances are equal
The test Statistic for this problem equals
a. 1.19
b. 0.84
c. 1.50
d. 0.67
1.19
s^2 32. 38
n. 24. 16
We want to test the hypothesis that the population variances are equal
The null hypothesis is to be tested at the 10% level of siginificance. The critical value from the table is
a. 2.24
b. 2.29
c. 2.13
d. 2.11
c. 2.13
n = 23 H0: o^2 >(greater or equal) 66
s^2 = 60. Ha: o^2 < 66
The test statistic has a value of
a. 24.20
b. 20.00
c. 20.91
d. 24.00
b. 20.00
n = 23 H0: o^2 >(greater or equal) 66
s^2 = 60. Ha: o^2 < 66
The null hypothesis
a. should be revised
b. should be rejected
c. None of these alternatives is correct
d. should not be rejected
d. should not be rejected
n = 23 s = 20 H0: o^2 <(less or equal) 500
Ha: o^2 >(greater or equal) 500
The test statistic for this problem equals
a. 0.63
b. 13.66
c. 12.68
d. 10.40
d. 10.40
In EXCEL, which of the following functions is used to conduct a hypothesis test for comparing two population variances?
a. CHI.INV
b. F-test
c. CHISQ.DIST
d. None of these answers are correct
b. F-test
The 97% confidence interval estimate for a popuation variance when a sample variance of 30 is obtained from a sample of 12 times is
a. 14.04 to 98.12
b. no correct answers
c. 15.05 to 86.48
d. 16.42 to 94.35
a. 14.04 to 98.12
The chi-square value for a one-tailed (upper tail) hypothesis test at 95% confidence and a sample size of 25 is
a. 36.4151
b. 37.6525
c. 39.3641
d. 33.1963
a. 36.4151
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. 2.10
b. 2.94
c. 2.45
d. 2.37
c. 2.45
The manager of the service department of a local car dealership has noted that the service 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. 8.58 to 39.79
b. 1.64 to 1.96
c. 4 to 15
c. 4 to 16
a. 8.58 to 39.79
The manager of the service department of a local car dealership has noted that the service times of a smaple of 30 new automobiles has a standard deviation 6 minutes. A 95% confidence interval estimate for the standard deviation of the serbice times for all their new automobile is
a. 16.05 fo 45.72
b. 2.93 to 6.31
c. 4.78 to 8.07
d. 22.83 to 65.06
4.78 to 8.07
The sampling distribution of the ratio of independent sample variance extracted from two normal populations with equal variances is the
a. normal distribution
b. chi-square distribtuion
c. t distribution
d. F distribtuion
d. F distribution
The sampling distribution of the ratio of two independent sample variances taken from normal populations with equal variances is
a. a t distribution
b. a chi-square distribution
c. an F distribtuion
d. a normal distribution
c. an F distribution
The symbol used for the variance of the population is
a. o
b. s^2
c. s
d. o^2
d. o^2
