1
CHAPTER 9 SECTION 1: SAMPLING DISTRIBUTIONS
MULTIPLE CHOICE
1.
The standard deviation of the sampling distribution of
X
is also called the:
a.
central limit theorem.
b.
standard error of the sample mean.
c.
finite population correction factor.
d.
population standard deviation.
ANS: B
PTS:
1
REF:
SECTION 9.1
2.
Random samples of size 49 are taken from an infinite population whose mean is 300 and standard
deviation is 21. The mean and standard error of the sample mean, respectively, are:
a.
300 and 21
b.
300 and 3
c.
300 and 0.43
d.
None of these choices.
ANS: B
PTS:
1
REF:
SECTION 9.1
3.
Given an infinite population with a mean of 75 and a standard deviation of 12, the probability that the
mean of a sample of 36 observations, taken at random from this population, is less than 78 is:
a.
0.9332
b.
0.5987
c.
1.5000
d.
None of these choices.
ANS: A
PTS:
1
REF:
SECTION 9.1
4.
An infinite population has a mean of 40 and a standard deviation of 15. A sample of size 100 is taken at
random from this population. The standard error of the sample mean equals:
a.
15
b.
15/100
c.
15/
√
100
d.
None of these choices.
ANS: C
PTS:
1
REF:
SECTION 9.1
5.
If all possible samples of size
n
are drawn from an infinite population with a mean of 15 and a standard
deviation of 5, then the standard error of the sample mean equals 1.0 for samples of size:
a.
5
b.
15
c.
25
d.
None of these choices.
ANS: C
PTS:
1
REF:
SECTION 9.1
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6.
As a general rule in computing the standard error of the sample mean, the finite population correction
factor is used only if the:
a.
sample size is smaller than 5% of the population size.
b.
sample size is greater than 5% of the sample size.
c.
sample size is more than half of the population size.
d.
None of these choices.
ANS: B
PTS:
1
REF:
SECTION 9.1
7.
Consider an infinite population with a mean of 160 and a standard deviation of 25. A random sample of
size 64 is taken from this population. The standard deviation of the sample mean equals:
a.
25
b.
25/64
c.
25/
√
64
d.
None of these choices.
ANS: C
PTS:
1
REF:
SECTION 9.1
8.
A sample of size 40 is taken from an infinite population whose mean and standard deviation are 68 and
12, respectively. The probability that the sample mean is larger than 70 equals
a.
P
(
Z
> 70)
b.
P
(
Z
> 2)
c.
P
(
Z
> 0.17)
d.
P
(
Z
> 1.05)
ANS: D
PTS:
1
REF:
SECTION 9.1
9.
The finite population correction factor should be used:
a.
whenever we are sampling from an infinite population.
b.
whenever we are sampling from a finite population.
c.
whenever the sample size is large compared to the population size.
d.
whenever the sample size is small compared to the population size.
ANS: C
PTS:
1
REF:
SECTION 9.1
10.
Random samples of size 81 are taken from an infinite population whose mean and standard deviation
are 45 and 9, respectively. The mean and standard error of the sampling distribution of the sample mean
are:
a.
45 and 9
b.
45/81 and 9/81
c.
45 and 9/
√
81
d.
45/
√
81 and 9/
√
81
ANS: C
PTS:
1
REF:
SECTION 9.1
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 Spring '10
 Kumar
 Normal Distribution, Standard Deviation, Mean, attorney

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