WGU C784 APPLIED PROBABILITY AND
STATISTICS COMPREHENSIVE EXAM
1. A researcher is measuring the weight of various newborn infants in a hospital. Which level
of measurement is being used?
A. Nominal
B. Ordinal
C. Ratio
D. Interval
Answer: C
Conceptual Explanation: Weight has a true zero point where ‘zero weight’ means the
absence of weight, and ratios like ‘twice as heavy’ are meaningful.
2. Which of the following measures of central tendency is most affected by extreme outliers
in a data set?
A. Mode
B. Median
C. Mean
D. Range
,Answer: C
Conceptual Explanation: The mean uses the value of every data point in its calculation,
making it highly sensitive to extreme values.
3. In a standard normal distribution, what percentage of data falls within two standard
deviations of the mean?
A. 68%
B. 50%
C. 99.7%
D. 95%
Answer: D
Conceptual Explanation: According to the Empirical Rule (68-95-99.7), approximately
95% of data in a normal distribution falls within two standard deviations.
4. If the correlation coefficient (r) between two variables is -0.85, what does this indicate
about the relationship?
A. A weak positive relationship
B. No relationship
C. A strong negative relationship
D. A strong positive relationship
Answer: C
, Conceptual Explanation: An r-value of -0.85 indicates a strong relationship because it is
close to -1, and it is negative because the sign is negative.
5. A bag contains 5 red marbles and 5 blue marbles. If you draw two marbles without
replacement, what is the probability that both are red?
A. 1/4
B. 1/2
C. 2/9
D. 2/5
Answer: C
Conceptual Explanation: The probability of the first being red is 5/10 (or 1/2). Without
replacement, the second red is 4/9. (1/2) * (4/9) = 4/18 = 2/9.
6. What is the primary difference between a parameter and a statistic?
A. A parameter describes a sample, a statistic describes a population
B. There is no difference between them
C. A parameter is always a whole number, a statistic is a decimal
D. A parameter is calculated from a population, a statistic is calculated from a sample
Answer: D
Conceptual Explanation: Parameters are numerical values summarizing population data,
while statistics summarize sample data.
STATISTICS COMPREHENSIVE EXAM
1. A researcher is measuring the weight of various newborn infants in a hospital. Which level
of measurement is being used?
A. Nominal
B. Ordinal
C. Ratio
D. Interval
Answer: C
Conceptual Explanation: Weight has a true zero point where ‘zero weight’ means the
absence of weight, and ratios like ‘twice as heavy’ are meaningful.
2. Which of the following measures of central tendency is most affected by extreme outliers
in a data set?
A. Mode
B. Median
C. Mean
D. Range
,Answer: C
Conceptual Explanation: The mean uses the value of every data point in its calculation,
making it highly sensitive to extreme values.
3. In a standard normal distribution, what percentage of data falls within two standard
deviations of the mean?
A. 68%
B. 50%
C. 99.7%
D. 95%
Answer: D
Conceptual Explanation: According to the Empirical Rule (68-95-99.7), approximately
95% of data in a normal distribution falls within two standard deviations.
4. If the correlation coefficient (r) between two variables is -0.85, what does this indicate
about the relationship?
A. A weak positive relationship
B. No relationship
C. A strong negative relationship
D. A strong positive relationship
Answer: C
, Conceptual Explanation: An r-value of -0.85 indicates a strong relationship because it is
close to -1, and it is negative because the sign is negative.
5. A bag contains 5 red marbles and 5 blue marbles. If you draw two marbles without
replacement, what is the probability that both are red?
A. 1/4
B. 1/2
C. 2/9
D. 2/5
Answer: C
Conceptual Explanation: The probability of the first being red is 5/10 (or 1/2). Without
replacement, the second red is 4/9. (1/2) * (4/9) = 4/18 = 2/9.
6. What is the primary difference between a parameter and a statistic?
A. A parameter describes a sample, a statistic describes a population
B. There is no difference between them
C. A parameter is always a whole number, a statistic is a decimal
D. A parameter is calculated from a population, a statistic is calculated from a sample
Answer: D
Conceptual Explanation: Parameters are numerical values summarizing population data,
while statistics summarize sample data.
