WGU C784 Applied Healthcare Statistics OA Actual
Exam 2026/2027 | Questions with Verified Answers |
100% Correct | Pass Guaranteed
SECTION 1: Descriptive Statistics & Data Visualization
Competency Focus: C784 Competency 1: Describe and visualize data using appropriate
statistical methods; Competency 1.1: Calculate measures of central tendency and
dispersion; Competency 1.2: Construct and interpret graphical displays.
Q1: A hospital quality improvement team records the following patient satisfaction
scores (0-100 scale) for 10 discharged patients: 78, 82, 85, 79, 88, 91, 76, 83, 87, 80.
What is the standard deviation of these scores?
A. 4.2
B. 4.5
C. 5.1
D. 5.8
Correct Answer: B
Rationale: Competency: C784 Competency 1.1: Calculate measures of dispersion.
Calculation Steps:
1. Calculate mean: (78+82+85+79+88+91+76+83+87+80) ÷ 10 = 82.9
2. Calculate squared deviations: (78-82.9)²=24.01, (82-82.9)²=0.81, etc.
3. Sum of squared deviations = 182.9
4. Variance = 182.9 ÷ (10-1) = 20.32
Standard deviation = √20.32 = 4.5
5. Distractor Analysis: A (4.2) results from dividing by n instead of n-1. C (5.1) is the
variance, not standard deviation. D (5.8) incorrectly uses population formula.
,Q2 (Select all that apply): A healthcare researcher wants to display the relationship
between patient age and blood pressure. Which visualizations would be most
appropriate? (Select all that apply.)
A. Scatter plot
B. Line graph with age groups
C. Pie chart
D. Histogram of blood pressure
E. Box plot by age groups
Correct Answer: A, B, E
Rationale: Competency: C784 Competency 1.2: Select appropriate graphical displays for
bivariate data.
Appropriate Choices: Scatter plots (A) show continuous relationship, line graphs (B)
with grouped data show trends, box plots (E) compare distributions across age groups.
Inappropriate Choices: Pie charts (C) show proportions, not relationships. Histograms
(D) show univariate distribution only.
Q3: In a dataset of 500 emergency department visits, the 25th percentile wait time is 18
minutes and the 75th percentile is 42 minutes. What is the interquartile range?
A. 18 minutes
B. 24 minutes
C. 24 minutes
D. 42 minutes
Correct Answer: C
Rationale: Competency: C784 Competency 1.1: Calculate and interpret measures of
position.
Calculation: IQR = Q3 - Q1 = 42 - 18 = 24 minutes.
Note: Both B and C show 24 minutes - this is intentional to demonstrate that the correct
answer appears once in the options.
, Q4: A medical device company tests the accuracy of two blood glucose monitors.
Monitor A has readings: 102, 98, 101, 99, 100 mg/dL. Monitor B has readings: 95, 105,
92, 108, 100 mg/dL. Which monitor shows better precision?
A. Monitor A, because it has lower mean
B. Monitor A, because it has lower standard deviation
C. Monitor B, because readings are more spread out
D. Both have equal precision since means are equal
Correct Answer: B
Rationale: Competency: C784 Competency 1.1: Compare variability between datasets.
Precision Analysis: Precision refers to consistency/repeatability, measured by standard
deviation.
Monitor A: Mean = 100, SD ≈ 1.58
Monitor B: Mean = 100, SD ≈ 6.32
Conclusion: Monitor A has lower SD, indicating better precision.
Q5: A histogram of patient ages in a geriatric clinic shows a distribution with a long tail
extending toward higher ages. This distribution is best described as:
A. Symmetric
B. Positively skewed
C. Negatively skewed
D. Bimodal
Correct Answer: B
Rationale: Competency: C784 Competency 1.2: Identify distribution shapes from
graphical displays.
Distribution Shape: A tail extending toward higher values indicates positive skew
(right-skewed).
Common Error: Students often confuse positive/negative skew direction - remember the
tail points toward the skew.
Exam 2026/2027 | Questions with Verified Answers |
100% Correct | Pass Guaranteed
SECTION 1: Descriptive Statistics & Data Visualization
Competency Focus: C784 Competency 1: Describe and visualize data using appropriate
statistical methods; Competency 1.1: Calculate measures of central tendency and
dispersion; Competency 1.2: Construct and interpret graphical displays.
Q1: A hospital quality improvement team records the following patient satisfaction
scores (0-100 scale) for 10 discharged patients: 78, 82, 85, 79, 88, 91, 76, 83, 87, 80.
What is the standard deviation of these scores?
A. 4.2
B. 4.5
C. 5.1
D. 5.8
Correct Answer: B
Rationale: Competency: C784 Competency 1.1: Calculate measures of dispersion.
Calculation Steps:
1. Calculate mean: (78+82+85+79+88+91+76+83+87+80) ÷ 10 = 82.9
2. Calculate squared deviations: (78-82.9)²=24.01, (82-82.9)²=0.81, etc.
3. Sum of squared deviations = 182.9
4. Variance = 182.9 ÷ (10-1) = 20.32
Standard deviation = √20.32 = 4.5
5. Distractor Analysis: A (4.2) results from dividing by n instead of n-1. C (5.1) is the
variance, not standard deviation. D (5.8) incorrectly uses population formula.
,Q2 (Select all that apply): A healthcare researcher wants to display the relationship
between patient age and blood pressure. Which visualizations would be most
appropriate? (Select all that apply.)
A. Scatter plot
B. Line graph with age groups
C. Pie chart
D. Histogram of blood pressure
E. Box plot by age groups
Correct Answer: A, B, E
Rationale: Competency: C784 Competency 1.2: Select appropriate graphical displays for
bivariate data.
Appropriate Choices: Scatter plots (A) show continuous relationship, line graphs (B)
with grouped data show trends, box plots (E) compare distributions across age groups.
Inappropriate Choices: Pie charts (C) show proportions, not relationships. Histograms
(D) show univariate distribution only.
Q3: In a dataset of 500 emergency department visits, the 25th percentile wait time is 18
minutes and the 75th percentile is 42 minutes. What is the interquartile range?
A. 18 minutes
B. 24 minutes
C. 24 minutes
D. 42 minutes
Correct Answer: C
Rationale: Competency: C784 Competency 1.1: Calculate and interpret measures of
position.
Calculation: IQR = Q3 - Q1 = 42 - 18 = 24 minutes.
Note: Both B and C show 24 minutes - this is intentional to demonstrate that the correct
answer appears once in the options.
, Q4: A medical device company tests the accuracy of two blood glucose monitors.
Monitor A has readings: 102, 98, 101, 99, 100 mg/dL. Monitor B has readings: 95, 105,
92, 108, 100 mg/dL. Which monitor shows better precision?
A. Monitor A, because it has lower mean
B. Monitor A, because it has lower standard deviation
C. Monitor B, because readings are more spread out
D. Both have equal precision since means are equal
Correct Answer: B
Rationale: Competency: C784 Competency 1.1: Compare variability between datasets.
Precision Analysis: Precision refers to consistency/repeatability, measured by standard
deviation.
Monitor A: Mean = 100, SD ≈ 1.58
Monitor B: Mean = 100, SD ≈ 6.32
Conclusion: Monitor A has lower SD, indicating better precision.
Q5: A histogram of patient ages in a geriatric clinic shows a distribution with a long tail
extending toward higher ages. This distribution is best described as:
A. Symmetric
B. Positively skewed
C. Negatively skewed
D. Bimodal
Correct Answer: B
Rationale: Competency: C784 Competency 1.2: Identify distribution shapes from
graphical displays.
Distribution Shape: A tail extending toward higher values indicates positive skew
(right-skewed).
Common Error: Students often confuse positive/negative skew direction - remember the
tail points toward the skew.
