QMB 3200 MIDTERM UCF PRACTICE
EXAM 2 QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025
1. A manager wants to estimate the average sales per month for all
stores in a region. Which of the following best describes the
population?
A) The sample of stores the manager selects
B) The average monthly sales of one store
C) All stores in the region
D) The standard deviation of sales of the sample
Answer: C
The population is the entire group the manager wants to learn about — in
this case, all stores in the region.
, 2. Which of the following is a point estimator for the population mean?
A) Sample mean
B) Population mean
C) Population standard deviation
D) Sample variance
Answer: A
A point estimator provides a single value as an estimate of a population
parameter. The sample mean is the point estimator of the population mean.
3. The sum of the deviations of each value from the mean for a dataset
will always be:
A) Equal to 1
B) Greater than zero
C) Less than zero
D) Equal to zero
Answer: D
By definition, the mean balances the data. So the sum of deviations from the
mean must be zero.
4. If the probability of an event is 0.20, what are the odds in favor of the
event?
A) 1 to 4
, B) 1 to 5
C) 4 to 1
D) 5 to 1
Answer: A
Odds in favor = P(A)/P(not A) = 0.20/0.80 = 1/4 or 1 to 4.
5. A discrete probability distribution must satisfy which of these
conditions?
A) Each probability must be greater than 1
B) All probabilities must sum to 0
C) Probabilities must be negative
D) Each probability must be between 0 and 1, and the total must equal
1
Answer: D
These are the two required conditions for any valid probability distribution.
6. Which measure of central tendency is most affected by outliers?
A) Median
B) Mode
C) Mean
D) Range
, Answer: C
The mean is pulled in the direction of extreme values, so it is most affected
by outliers.
7. If a random variable follows a normal distribution with mean 100 and
standard deviation 10, what is the probability of observing a value
greater than 120?
A) 0.5000
B) 0.8413
C) 0.1587
D) 0.0228
Answer: C
Z = (120 - 100)/10 = 2. P(Z > 2) = 0.0228. Be careful! But the correct value is
0.0228, which is not an option here, so the closest option is 0.0228 which
should have been included.
(Correction: The correct answer should be D. P(Z > 2) = 0.0228.)
8. If the standard deviation of a population is 15, what is the standard
error of the mean for a sample size of 25?
A) 15
B) 3
EXAM 2 QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025
1. A manager wants to estimate the average sales per month for all
stores in a region. Which of the following best describes the
population?
A) The sample of stores the manager selects
B) The average monthly sales of one store
C) All stores in the region
D) The standard deviation of sales of the sample
Answer: C
The population is the entire group the manager wants to learn about — in
this case, all stores in the region.
, 2. Which of the following is a point estimator for the population mean?
A) Sample mean
B) Population mean
C) Population standard deviation
D) Sample variance
Answer: A
A point estimator provides a single value as an estimate of a population
parameter. The sample mean is the point estimator of the population mean.
3. The sum of the deviations of each value from the mean for a dataset
will always be:
A) Equal to 1
B) Greater than zero
C) Less than zero
D) Equal to zero
Answer: D
By definition, the mean balances the data. So the sum of deviations from the
mean must be zero.
4. If the probability of an event is 0.20, what are the odds in favor of the
event?
A) 1 to 4
, B) 1 to 5
C) 4 to 1
D) 5 to 1
Answer: A
Odds in favor = P(A)/P(not A) = 0.20/0.80 = 1/4 or 1 to 4.
5. A discrete probability distribution must satisfy which of these
conditions?
A) Each probability must be greater than 1
B) All probabilities must sum to 0
C) Probabilities must be negative
D) Each probability must be between 0 and 1, and the total must equal
1
Answer: D
These are the two required conditions for any valid probability distribution.
6. Which measure of central tendency is most affected by outliers?
A) Median
B) Mode
C) Mean
D) Range
, Answer: C
The mean is pulled in the direction of extreme values, so it is most affected
by outliers.
7. If a random variable follows a normal distribution with mean 100 and
standard deviation 10, what is the probability of observing a value
greater than 120?
A) 0.5000
B) 0.8413
C) 0.1587
D) 0.0228
Answer: C
Z = (120 - 100)/10 = 2. P(Z > 2) = 0.0228. Be careful! But the correct value is
0.0228, which is not an option here, so the closest option is 0.0228 which
should have been included.
(Correction: The correct answer should be D. P(Z > 2) = 0.0228.)
8. If the standard deviation of a population is 15, what is the standard
error of the mean for a sample size of 25?
A) 15
B) 3
