BSTAT 3321 Mock Exam II Practice Student
MULTIPLE CHOICE
Choose the one alternative that best completes the statement
or answers the question.
1) A nursery sells trees of different types and heights. These trees average 60 inches in height
with a standard deviation of 19 inches. Suppose that 60 pine trees are sold for planting at City
Hall. What is the standard deviation for the sample mean? Use only two decimals.
A) 5
B) 4.02
C) 19
D) 2.45
2) If a population is known to be normally distributed, what can be said about the sampling
distribution of the sample mean drawn from this population?
A) For any sample size n, the sampling distribution of the sample mean is normally
distributed.
B) For a sample size n < 50, the sampling distribution of the sample mean is normally
distributed.
C) For a sample size n < 30, the sampling distribution of the sample mean is normally
distributed.
D) For a sample size n > 30, the sampling distribution of the sample mean is normally
distributed.
3) Over the entire six years that students attend an Ohio elementary school, they are absent, on
average, 28 days due to influenza. Assume that the standard deviation over this time period is
o =9 days. Upon graduation from elementary school, a random sample of 36 students is
taken and asked how many days of school they missed due to influenza.
The probability that the sample mean is less than 30 school days is
A) 0.0918
B) 0.4129
C) 0.5871
D) 0.9088
Version 1 1
, BSTAT 3321 Mock Exam II Practice Student
4) Suppose that, on average, electricians earn approximately $54,000 per year in the United
States. Assume that the distribution for electricians’ yearly earnings is normally distributed
and that the standard deviation is $12,000.
‘What is the probability that the average salary of four randomly selected electricians exceeds
$60,000?
A) 0.1587
B) 0.3085
C) 0.6915
D) 0.8413
5) According to the central limit theorem, the sampling distribution of the sample means is
approximately normal if
A) the underlying population is not normal.
B) the sample size n > 30
C) the standard deviation of the population is large.
D) both the underlying population is not normal and the sample size n > 30 are correct.
6) Using the central limit theorem, applied to the sampling distribution of the sample
proportion, what conditions must be met?
A) P =54¢Ml-p) <5
B) M =5udn(l-p)=5
C) o =5.,4n1l-p) =5
D) P =5adn(l-p)
=5
7) A random sample of size 100 is taken from a population with the proportion p = 0.60.
‘What are the expected value and the standard error for the sampling distribution of the
sample proportion?
A) 0.006 and 0.0024, respectively.
B) 0.060 and 0.049, respectively.
C) 0.600 and 0.0024, respectively.
D) 0.600 and 0.049, respectively.
Version 1 2
MULTIPLE CHOICE
Choose the one alternative that best completes the statement
or answers the question.
1) A nursery sells trees of different types and heights. These trees average 60 inches in height
with a standard deviation of 19 inches. Suppose that 60 pine trees are sold for planting at City
Hall. What is the standard deviation for the sample mean? Use only two decimals.
A) 5
B) 4.02
C) 19
D) 2.45
2) If a population is known to be normally distributed, what can be said about the sampling
distribution of the sample mean drawn from this population?
A) For any sample size n, the sampling distribution of the sample mean is normally
distributed.
B) For a sample size n < 50, the sampling distribution of the sample mean is normally
distributed.
C) For a sample size n < 30, the sampling distribution of the sample mean is normally
distributed.
D) For a sample size n > 30, the sampling distribution of the sample mean is normally
distributed.
3) Over the entire six years that students attend an Ohio elementary school, they are absent, on
average, 28 days due to influenza. Assume that the standard deviation over this time period is
o =9 days. Upon graduation from elementary school, a random sample of 36 students is
taken and asked how many days of school they missed due to influenza.
The probability that the sample mean is less than 30 school days is
A) 0.0918
B) 0.4129
C) 0.5871
D) 0.9088
Version 1 1
, BSTAT 3321 Mock Exam II Practice Student
4) Suppose that, on average, electricians earn approximately $54,000 per year in the United
States. Assume that the distribution for electricians’ yearly earnings is normally distributed
and that the standard deviation is $12,000.
‘What is the probability that the average salary of four randomly selected electricians exceeds
$60,000?
A) 0.1587
B) 0.3085
C) 0.6915
D) 0.8413
5) According to the central limit theorem, the sampling distribution of the sample means is
approximately normal if
A) the underlying population is not normal.
B) the sample size n > 30
C) the standard deviation of the population is large.
D) both the underlying population is not normal and the sample size n > 30 are correct.
6) Using the central limit theorem, applied to the sampling distribution of the sample
proportion, what conditions must be met?
A) P =54¢Ml-p) <5
B) M =5udn(l-p)=5
C) o =5.,4n1l-p) =5
D) P =5adn(l-p)
=5
7) A random sample of size 100 is taken from a population with the proportion p = 0.60.
‘What are the expected value and the standard error for the sampling distribution of the
sample proportion?
A) 0.006 and 0.0024, respectively.
B) 0.060 and 0.049, respectively.
C) 0.600 and 0.0024, respectively.
D) 0.600 and 0.049, respectively.
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