Latest 2026/2027 WGU D772 STATISTICAL DATA LITERACY
exam verified with correct answers plus rationales
1. A researcher records the number of hours each student studies per week. What type of
variable is this?
A. Categorical
B. Quantitative
C. Nominal
D. Ordinal
Correct Answer: B
Rationale: Hours studied is numerical and can be measured quantitatively.
2. A survey asks respondents to identify their preferred method of transportation: bus,
train, car, bicycle, or walking. What type of variable is this?
A. Quantitative
B. Continuous
C. Categorical
D. Ratio
Correct Answer: C
Rationale: Transportation method represents categories rather than numerical measurements.
3. A dataset contains the values 4, 6, 8, 10, and 12. What is the mean?
A. 6
B. 8
C. 10
D. 12
Correct Answer: B
Rationale: Add the values and divide by the five observations: (4 + 6 + 8 + 10 + 12) ÷ 5 = 8.
,4. A dataset contains 3, 5, 7, 9, and 20. Which measure of center is least affected by the
extreme value?
A. Mean
B. Median
C. Range
D. Standard deviation
Correct Answer: B
Rationale: The median is resistant to extreme observations, whereas the mean can be pulled
substantially toward an outlier.
5. A dataset has values of 12, 15, 18, 21, and 30. What is the range?
A. 12
B. 15
C. 18
D. 30
Correct Answer: C
Rationale: Range = maximum − minimum = 30 − 12 = 18.
6. What does a standard deviation primarily describe?
A. The number of observations
B. The spread of observations around the mean
C. The highest observation only
D. The sample size
Correct Answer: B
Rationale: Standard deviation measures the typical amount of variation of observations around
their mean.
7. A dataset has a very large standard deviation. What does this generally indicate?
A. The observations are widely dispersed
B. All observations are identical
,C. The mean must equal zero
D. The sample contains no variation
Correct Answer: A
Rationale: A larger standard deviation indicates greater variability around the mean.
8. A histogram shows most observations concentrated on the left side with a long tail
extending to the right. How is the distribution described?
A. Left-skewed
B. Right-skewed
C. Symmetric
D. Uniform
Correct Answer: B
Rationale: Skewness is named for the direction of the longer tail. A tail extending toward larger
values indicates right skew.
9. In a perfectly symmetric distribution, which relationship is generally expected?
A. Mean and median are approximately equal
B. Mean is always zero
C. Median is always larger than the mean
D. Range is always zero
Correct Answer: A
Rationale: In a symmetric distribution without substantial outliers, the mean and median tend to
be approximately equal.
10. What does the interquartile range measure?
A. The spread of the middle 50% of observations
B. The total number of observations
C. The largest observation only
D. The mean of the dataset
Correct Answer: A
, Rationale: IQR is calculated as Q3 − Q1 and represents the spread of the middle 50% of the
data.
11. A value lies at the 75th percentile of a dataset. What does this mean?
A. Approximately 75% of observations are at or below that value
B. The value is 75 units above the mean
C. The value is the maximum
D. Exactly 75 observations exist
Correct Answer: A
Rationale: A percentile indicates the relative position of an observation within a distribution.
12. A researcher randomly selects 100 employees from a company of 5,000 employees.
What is the group of 100 employees called?
A. Population
B. Sample
C. Parameter
D. Census
Correct Answer: B
Rationale: A sample is a subset of a population selected for study.
13. The average salary of every employee in a company is calculated. What is this value
considered?
A. Sample statistic
B. Population parameter
C. Sampling error
D. Residual
Correct Answer: B
Rationale: A numerical characteristic calculated from an entire population is a population
parameter.
exam verified with correct answers plus rationales
1. A researcher records the number of hours each student studies per week. What type of
variable is this?
A. Categorical
B. Quantitative
C. Nominal
D. Ordinal
Correct Answer: B
Rationale: Hours studied is numerical and can be measured quantitatively.
2. A survey asks respondents to identify their preferred method of transportation: bus,
train, car, bicycle, or walking. What type of variable is this?
A. Quantitative
B. Continuous
C. Categorical
D. Ratio
Correct Answer: C
Rationale: Transportation method represents categories rather than numerical measurements.
3. A dataset contains the values 4, 6, 8, 10, and 12. What is the mean?
A. 6
B. 8
C. 10
D. 12
Correct Answer: B
Rationale: Add the values and divide by the five observations: (4 + 6 + 8 + 10 + 12) ÷ 5 = 8.
,4. A dataset contains 3, 5, 7, 9, and 20. Which measure of center is least affected by the
extreme value?
A. Mean
B. Median
C. Range
D. Standard deviation
Correct Answer: B
Rationale: The median is resistant to extreme observations, whereas the mean can be pulled
substantially toward an outlier.
5. A dataset has values of 12, 15, 18, 21, and 30. What is the range?
A. 12
B. 15
C. 18
D. 30
Correct Answer: C
Rationale: Range = maximum − minimum = 30 − 12 = 18.
6. What does a standard deviation primarily describe?
A. The number of observations
B. The spread of observations around the mean
C. The highest observation only
D. The sample size
Correct Answer: B
Rationale: Standard deviation measures the typical amount of variation of observations around
their mean.
7. A dataset has a very large standard deviation. What does this generally indicate?
A. The observations are widely dispersed
B. All observations are identical
,C. The mean must equal zero
D. The sample contains no variation
Correct Answer: A
Rationale: A larger standard deviation indicates greater variability around the mean.
8. A histogram shows most observations concentrated on the left side with a long tail
extending to the right. How is the distribution described?
A. Left-skewed
B. Right-skewed
C. Symmetric
D. Uniform
Correct Answer: B
Rationale: Skewness is named for the direction of the longer tail. A tail extending toward larger
values indicates right skew.
9. In a perfectly symmetric distribution, which relationship is generally expected?
A. Mean and median are approximately equal
B. Mean is always zero
C. Median is always larger than the mean
D. Range is always zero
Correct Answer: A
Rationale: In a symmetric distribution without substantial outliers, the mean and median tend to
be approximately equal.
10. What does the interquartile range measure?
A. The spread of the middle 50% of observations
B. The total number of observations
C. The largest observation only
D. The mean of the dataset
Correct Answer: A
, Rationale: IQR is calculated as Q3 − Q1 and represents the spread of the middle 50% of the
data.
11. A value lies at the 75th percentile of a dataset. What does this mean?
A. Approximately 75% of observations are at or below that value
B. The value is 75 units above the mean
C. The value is the maximum
D. Exactly 75 observations exist
Correct Answer: A
Rationale: A percentile indicates the relative position of an observation within a distribution.
12. A researcher randomly selects 100 employees from a company of 5,000 employees.
What is the group of 100 employees called?
A. Population
B. Sample
C. Parameter
D. Census
Correct Answer: B
Rationale: A sample is a subset of a population selected for study.
13. The average salary of every employee in a company is calculated. What is this value
considered?
A. Sample statistic
B. Population parameter
C. Sampling error
D. Residual
Correct Answer: B
Rationale: A numerical characteristic calculated from an entire population is a population
parameter.
