1. Find the critical value za/2that corresponds to a degree of confidence of 98%. Select one:
a. 2.575
b. 1.75
c. 2.33
d. 2.05
2. Find the margin of error for the 95% confidence interval used to estimate the population proportion.
n= 163,x= 96 Select one:
a. 0.00291
b. 0.0755
c. 0.132
d. 0.0680
3. Use the given degree of confidence and sample data to construct a confidence interval for the population proportionp.
n= 165,x= 138; 95 percent Select one:
a. 0.779 < p < 0.892
b. 0.780 < p < 0.893
c. 0.790 < p < 0.882
d. 0.791 < p < 0.881
4. Find the minimum sample size you should use to assure that your estimate of Margin of error: 0.04; confidence level: 99%; from a prior study,
a. 272
b. 19
c. 563
d. 469
5. 459 randomly selected light bulbs were tested in a laboratory, 291 lasted more than 500 hours.
Find a point estimate of the true proportion of all light bulbs that last more than 500 hours. Select one:
a. 0.634
b. 0.632
c. 0.366
d. 0.388
6. A researcher is interested in estimating the proportion of voters who favor a tax on e-commerce.
Based on a sample of 250 people, she obtains the following 99% confidence interval for the population proportion p:
0.113
Which of the statements below is a valid interpretation of this confidence interval? Select one:
a. If 100 different samples of size 250 were selected and, based on each sample, a confidence interval was constructed, exactly 99 of these confidence intervals would contain the true value of p.
b. If many different samples of size 250 were selected and, based on each sample, a confidence interval was constructed, in the long run 99% of the confidence intervals would contain the true value of p.
c. There is a 99% chance that the true value of p lies between 0.113 and 0.171.
d. If many different samples of size 250 were selected and, based on each sample, a confidence interval was constructed, 99% of the time the true value of p would lie between 0.113 and 0.171.
7. Use the confidence level and sample data to find the margin of error E. College students' annual earnings: 99% confidence;n = 74, = $3967,s = $874 Select one:
a. $262
b. $1187
c. $9
d. $237
8. Use the confidence level and sample data to find a confidence interval for estimating the populationm. A group of 56 randomly selected students have a mean score of 30.8 with a standard deviation of 4.5 on a placement test. What is the 90 percent confidence interval for the mean score,m, of all students taking the test? Select one:
a. 29.2 < m < 32.4
b. 29.8 < m < 31.8
c. 29.4 < m < 32.2
d. 29.6 < m < 32.0
9. Use the margin of error, confidence level, and standard deviation s to find the minimum sample size required to estimate an unknown population mean.
Margin of error: $139, confidence level: 95%,s= $513 Select one:
a. 53
b. 46
c. 3
d. 5
10. Do one of the following, as appropriate: (a) Find the critical value za/2, (b) find the critical value ta/2, (c) state that neither the normal nor the t distribution applies.
99%;n= 17;sis unknown; population appears to be normally distributed. Select one:
a. za/2= 2.575
b. ta/2= 2.921
c. ta/2 = 2.898