WGU C207 Data-Driven Decision-Making Final Exam
Practice Test Actual 2025/2026 with Detailed
Rationales | 100% Verified | Pass Guaranteed – A+
Graded
SECTION 1: Descriptive & Inferential Statistics (12 questions)
Q1: A dataset has a mean of 50 and a standard deviation of 10. Approximately what
percentage of data falls between 40 and 60?
A. 68% [CORRECT]
B. 95%
C. 99.7%
D. 50%
Correct Answer: A
Rationale: Correct because in a normal distribution, ±1 standard deviation from the
mean contains approximately 68% of data. This is a fundamental concept of the
empirical rule (68-95-99.7 rule). The range 40-60 represents one standard deviation
below and above the mean (50 ± 10).
Q2: The standard deviation of a sample is:
A. The average distance from the mean
B. The square root of the variance [CORRECT]
C. The range divided by 4
D. The mean divided by n
Correct Answer: B
Rationale: Correct because the standard deviation is the square root of the variance,
representing the average distance of data points from the mean and providing a
measure of data dispersion in the original units.
Q3: Which measure of central tendency is most affected by outliers?
A. Mean [CORRECT]
B. Median
C. Mode
,D. Range
Correct Answer: A
Rationale: Correct because the mean is sensitive to extreme values or outliers, unlike
the median which is robust. A single outlier can significantly pull the mean in one
direction, making the median preferred for skewed distributions.
Q4: A sample of 100 customers has a mean satisfaction score of 4.2 with a standard
deviation of 0.8. The standard error of the mean is:
A. 0.08 [CORRECT]
B. 0.8
C. 4.2
D. 0.008
Correct Answer: A
Rationale: Correct because SEM = standard deviation / √n = 0.8 / √100 = 0. =
0.08. The standard error measures the precision of the sample mean as an estimate
of the population mean.
Q5: A confidence interval provides:
A. A single point estimate
B. A range of values containing the population parameter with a certain confidence
[CORRECT]
C. The exact population parameter
D. The standard error
Correct Answer: B
Rationale: Correct because a confidence interval is a range of values that is likely to
contain the population parameter with a specified level of confidence (typically 95%
or 99%), accounting for sampling variability.
Q6: A p-value of 0.03 in a hypothesis test indicates:
A. The null hypothesis is true
B. There is a 3% chance of observing the data if the null hypothesis is true
[CORRECT]
C. The alternative hypothesis is true
D. There is a 97% chance the null hypothesis is false
Correct Answer: B
Rationale: Correct because a p-value represents the probability of observing the
sample data (or more extreme) assuming the null hypothesis is true. A p-value of
0.03 is less than the typical alpha of 0.05, suggesting statistical significance.
, Q7: A Type I error in hypothesis testing occurs when:
A. The null hypothesis is rejected when it is true [CORRECT]
B. The null hypothesis is not rejected when it is false
C. The alternative hypothesis is rejected when it is true
D. The sample size is too small
Correct Answer: A
Rationale: Correct because Type I error (false positive) is rejecting a true null
hypothesis. The probability of Type I error is controlled by alpha (α), typically set at
0.05.
Q8: ANOVA is used to:
A. Compare means of two groups
B. Compare means of three or more groups [CORRECT]
C. Measure correlation
D. Predict outcomes
Correct Answer: B
Rationale: Correct because ANOVA (Analysis of Variance) compares means across
three or more groups to determine if there is a statistically significant difference,
using the F-statistic to test the null hypothesis.
Q9: The central limit theorem states that:
A. All distributions are normal
B. The mean of a sample is equal to the population mean
C. The distribution of sample means approaches normal as sample size increases
[CORRECT]
D. The standard deviation is always zero
Correct Answer: C
Rationale: Correct because the CLT states that as sample size increases (typically n
≥ 30), the sampling distribution of the mean approaches a normal distribution
regardless of the population distribution shape.
Q10: The null hypothesis in a test typically states:
A. There is a significant effect
B. There is no effect or no difference [CORRECT]
C. The sample mean equals the population mean
D. The alternative is false
Correct Answer: B
Practice Test Actual 2025/2026 with Detailed
Rationales | 100% Verified | Pass Guaranteed – A+
Graded
SECTION 1: Descriptive & Inferential Statistics (12 questions)
Q1: A dataset has a mean of 50 and a standard deviation of 10. Approximately what
percentage of data falls between 40 and 60?
A. 68% [CORRECT]
B. 95%
C. 99.7%
D. 50%
Correct Answer: A
Rationale: Correct because in a normal distribution, ±1 standard deviation from the
mean contains approximately 68% of data. This is a fundamental concept of the
empirical rule (68-95-99.7 rule). The range 40-60 represents one standard deviation
below and above the mean (50 ± 10).
Q2: The standard deviation of a sample is:
A. The average distance from the mean
B. The square root of the variance [CORRECT]
C. The range divided by 4
D. The mean divided by n
Correct Answer: B
Rationale: Correct because the standard deviation is the square root of the variance,
representing the average distance of data points from the mean and providing a
measure of data dispersion in the original units.
Q3: Which measure of central tendency is most affected by outliers?
A. Mean [CORRECT]
B. Median
C. Mode
,D. Range
Correct Answer: A
Rationale: Correct because the mean is sensitive to extreme values or outliers, unlike
the median which is robust. A single outlier can significantly pull the mean in one
direction, making the median preferred for skewed distributions.
Q4: A sample of 100 customers has a mean satisfaction score of 4.2 with a standard
deviation of 0.8. The standard error of the mean is:
A. 0.08 [CORRECT]
B. 0.8
C. 4.2
D. 0.008
Correct Answer: A
Rationale: Correct because SEM = standard deviation / √n = 0.8 / √100 = 0. =
0.08. The standard error measures the precision of the sample mean as an estimate
of the population mean.
Q5: A confidence interval provides:
A. A single point estimate
B. A range of values containing the population parameter with a certain confidence
[CORRECT]
C. The exact population parameter
D. The standard error
Correct Answer: B
Rationale: Correct because a confidence interval is a range of values that is likely to
contain the population parameter with a specified level of confidence (typically 95%
or 99%), accounting for sampling variability.
Q6: A p-value of 0.03 in a hypothesis test indicates:
A. The null hypothesis is true
B. There is a 3% chance of observing the data if the null hypothesis is true
[CORRECT]
C. The alternative hypothesis is true
D. There is a 97% chance the null hypothesis is false
Correct Answer: B
Rationale: Correct because a p-value represents the probability of observing the
sample data (or more extreme) assuming the null hypothesis is true. A p-value of
0.03 is less than the typical alpha of 0.05, suggesting statistical significance.
, Q7: A Type I error in hypothesis testing occurs when:
A. The null hypothesis is rejected when it is true [CORRECT]
B. The null hypothesis is not rejected when it is false
C. The alternative hypothesis is rejected when it is true
D. The sample size is too small
Correct Answer: A
Rationale: Correct because Type I error (false positive) is rejecting a true null
hypothesis. The probability of Type I error is controlled by alpha (α), typically set at
0.05.
Q8: ANOVA is used to:
A. Compare means of two groups
B. Compare means of three or more groups [CORRECT]
C. Measure correlation
D. Predict outcomes
Correct Answer: B
Rationale: Correct because ANOVA (Analysis of Variance) compares means across
three or more groups to determine if there is a statistically significant difference,
using the F-statistic to test the null hypothesis.
Q9: The central limit theorem states that:
A. All distributions are normal
B. The mean of a sample is equal to the population mean
C. The distribution of sample means approaches normal as sample size increases
[CORRECT]
D. The standard deviation is always zero
Correct Answer: C
Rationale: Correct because the CLT states that as sample size increases (typically n
≥ 30), the sampling distribution of the mean approaches a normal distribution
regardless of the population distribution shape.
Q10: The null hypothesis in a test typically states:
A. There is a significant effect
B. There is no effect or no difference [CORRECT]
C. The sample mean equals the population mean
D. The alternative is false
Correct Answer: B
