Sampling Techniques

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CHAPTER 7—SAMPLING AND SAMPLING DISTRIBUTIONS

MULTIPLE CHOICE

1.From a group of 12 students, we want to select a random sample of 4 students to serve on a university committee. How many different random samples of 4 students can be selected? a.|48|
b.|20,736|
c.|16|
d.|495|

ANS:D

2.Parameters are
a.|numerical characteristics of a sample|
b.|numerical characteristics of a population|
c.|the averages taken from a sample|
d.|numerical characteristics of either a sample or a population|

ANS:B

3.How many simple random samples of size 3 can be selected from a population of size 7? a.|7|
b.|21|
c.|35|
d.|343|

ANS:C

4.Sampling distribution of is the
a.|probability distribution of the sample mean|
b.|probability distribution of the sample proportion|
c.|mean of the sample|
d.|mean of the population|

ANS:A

5.A simple random sample of 100 observations was taken from a large population. The sample mean and the standard deviation were determined to be 80 and 12 respectively. The standard error of the mean is a.|1.20|

b.|0.12|
c.|8.00|
d.|0.80|

ANS:A

6.A population has a standard deviation of 16. If a sample of size 64 is selected from this population, what is the probability that the sample mean will be within 2 of the population mean? a.|0.6826|

b.|0.3413|
c.|-0.6826|
d.|Since the mean is not given, there is no answer to this question.|

ANS:A

7.The probability distribution of all possible values of the sample proportion is the a.|probability density function of |
b.|sampling distribution of |
c.|same as , since it considers all possible values of the sample proportion| d.|sampling distribution of |

ANS:D

8.In computing the standard error of the mean, the finite population correction factor is used when a.|N/n > 0.05|
b.|N/n 0.05|
c.|n/N > 0.05|
d.|n/N 30|

ANS:C

9.Convenience sampling is an example of
a.|probabilistic sampling|
b.|stratified sampling|
c.|nonprobabilistic sampling|
d.|cluster sampling|

ANS:C

10.Which of the following is an example of nonprobabilistic sampling? a.|simple random sampling|
b.|stratified simple random sampling|
c.|cluster sampling|
d.|judgment sampling|

ANS:D

11.Stratified random sampling is a method of selecting a sample in which a.|the sample is first divided into strata, and then random samples are taken from each stratum| b.|various strata are selected from the sample|

c.|the population is first divided into strata, and then random samples are drawn from each stratum| d.|None of these alternatives is correct.|

ANS:C

12.A population consists of 500 elements. We want to draw a simple random sample of 50 elements from this population. On the first selection, the probability of an element being selected is a.|0.100|

b.|0.010|
c.|0.001|
d.|0.002|

ANS:D

13.The closer the sample mean is to the population mean,
a.|the larger the sampling error|
b.|the smaller the sampling error|
c.|the sampling error equals 1|
d.|None of these alternatives is correct.|

ANS:B

14.Since the sample size is always smaller than the size of the population, the sample mean a.|must always be smaller than the population mean|
b.|must be larger than the population mean|
c.|must be equal to the population mean|
d.|can be smaller, larger, or equal to the population mean|

ANS:D

15.As the sample size increases, the
a.|standard deviation of the population decreases|
b.|population mean increases|
c.|standard error of the mean decreases|
d.|standard error of the mean increases|

ANS:C

16.A simple random sample from an infinite population is a sample selected such that a.|each element is selected independently and from the same population| b.|each element has a 0.5 probability of being selected|

c.|each element has a probability of at least 0.5 of being selected| d.|the probability of being selected changes|

ANS:A

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