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 healthcare data using
appropriate statistical methods and graphical displays.
Q1: A healthcare administrator collects wait time data (minutes) from an emergency
department: [18, 22, 15, 30, 25, 20, 35, 28, 19, 24]. What is the median wait time?
A. 22 minutes
B. 23 minutes
C. 24 minutes
D. 25 minutes
Correct Answer: B
Rationale: Competency: C784 Competency 1.2: Calculate and interpret measures of
central tendency.
Calculation Steps:
1. Arrange data in ascending order: [15, 18, 19, 20, 22, 24, 25, 28, 30, 35]
2. With n=10 (even number), median = average of values in positions 5 and 6
3. Position 5 value = 22; Position 6 value = 24
Median = (22 + 24) ÷ 2 = 23 minutes
4. Distractor Analysis: A (22) is position 5 only, not the median. C (24) is position 6
only. D (25) is the 7th value and represents the 70th percentile, not median.
,Q2 (Select all that apply): Which of the following visualizations are appropriate for
displaying the relationship between two continuous variables, such as patient age and
blood pressure readings? (Select all that apply.)
A. Scatter plot
B. ** scatter plot with trend line**
C. Pie chart
D. Correlation matrix heat map
E. Bar chart
Correct Answer: A, B, D
Rationale: Competency: C784 Competency 1.3: Select appropriate graphical displays for
different healthcare data types.
Appropriate Visualizations: Scatter plots (A) and their variants with trend lines (B)
directly display bivariate continuous relationships. Correlation matrix heat maps (D) can
visualize correlation strength between multiple continuous variables.
Inappropriate Choices: Pie charts (C) show proportional composition of categorical
data. Bar charts (E) compare discrete categories, not continuous relationships.
Q3: A hospital tracks daily patient census over a month. The data shows a right-skewed
distribution with a mean of 145 patients and a median of 138 patients. Which statement
best describes this distribution?
A. The mean underestimates the typical patient census
B. The presence of high census outliers is pulling the mean upward above the median
C. The distribution is symmetrical
D. The mode must be higher than the mean
Correct Answer: B
Rationale: Competency: C784 Competency 1.1: Analyze distribution shapes and their
implications for healthcare data.
,Distribution Analysis: In right-skewed distributions, the tail extends toward higher
values. The mean is sensitive to extreme values and gets pulled toward the tail, while
the median remains robust. Since mean (145) > median (138), high outliers exist.
Distractor Analysis: A is incorrect—the mean overestimates due to high outliers. C is
opposite of right-skewed. D cannot be determined; mode could be lower than both.
Q4: Calculate the interquartile range (IQR) for the following sorted data representing
patient satisfaction scores: [62, 68, 72, 75, 78, 82, 85, 88, 92, 95, 98]
A. 15
B. 20
C. 23
D. 36
Correct Answer: B
Rationale: Competency: C784 Competency 1.2: Calculate and interpret measures of
variability.
Calculation Steps:
1. Q1 (25th percentile) = median of lower half: [62, 68, 72, 75, 78] → Q1 = 72
2. Q3 (75th percentile) = median of upper half: [85, 88, 92, 95, 98] → Q3 = 92
IQR = Q3 - Q1 = 92 - 72 = 20
3. Distractor Analysis: A (15) miscalculates Q1 or Q3. C (23) uses incorrect
percentile positions. D (36) is the range (98-62), not IQR.
Q5: A quality improvement team wants to display the percentage breakdown of patient
insurance types (Medicare, Medicaid, Private, Uninsured). Which visualization is most
appropriate?
A. Histogram
B. Box plot
C. Pie chart or bar chart
D. Scatter plot
, Correct Answer: C
Rationale: Competency: C784 Competency 1.3: Select appropriate graphical displays for
categorical healthcare data.
Categorical Composition: Pie charts and bar charts effectively display proportional
breakdowns of categorical data like insurance type percentages.
Inappropriate Choices: Histograms (A) and box plots (B) display continuous data
distributions. Scatter plots (D) show relationships between continuous variables.
Q6: In a dataset of 500 patients, the mean length of stay is 4.5 days with a standard
deviation of 2.1 days. What is the z-score for a patient who stayed 8.7 days?
A. 1.5
B. 2.0
C. 2.5
D. 4.1
Correct Answer: B
Rationale: Competency: C784 Competency 1.4: Calculate and interpret standardized
scores in healthcare contexts.
Calculation: z = (X - μ) / σ = (8.7 - 4.5) / 2.1 = 4..1 = 2.0
Interpretation: This patient stayed 2 standard deviations above the mean, a statistically
unusual duration.
Distractor Analysis: A (1.5) uses incorrect numerator (3.15). C (2.5) misdivides
(5.25/2.1). D (4.1) is the actual LOS, not the z-score.
Q7: Which measure of central tendency is most appropriate for reporting typical
hospital length of stay when the data is heavily right-skewed with several extreme
outliers?
A. Mean
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 healthcare data using
appropriate statistical methods and graphical displays.
Q1: A healthcare administrator collects wait time data (minutes) from an emergency
department: [18, 22, 15, 30, 25, 20, 35, 28, 19, 24]. What is the median wait time?
A. 22 minutes
B. 23 minutes
C. 24 minutes
D. 25 minutes
Correct Answer: B
Rationale: Competency: C784 Competency 1.2: Calculate and interpret measures of
central tendency.
Calculation Steps:
1. Arrange data in ascending order: [15, 18, 19, 20, 22, 24, 25, 28, 30, 35]
2. With n=10 (even number), median = average of values in positions 5 and 6
3. Position 5 value = 22; Position 6 value = 24
Median = (22 + 24) ÷ 2 = 23 minutes
4. Distractor Analysis: A (22) is position 5 only, not the median. C (24) is position 6
only. D (25) is the 7th value and represents the 70th percentile, not median.
,Q2 (Select all that apply): Which of the following visualizations are appropriate for
displaying the relationship between two continuous variables, such as patient age and
blood pressure readings? (Select all that apply.)
A. Scatter plot
B. ** scatter plot with trend line**
C. Pie chart
D. Correlation matrix heat map
E. Bar chart
Correct Answer: A, B, D
Rationale: Competency: C784 Competency 1.3: Select appropriate graphical displays for
different healthcare data types.
Appropriate Visualizations: Scatter plots (A) and their variants with trend lines (B)
directly display bivariate continuous relationships. Correlation matrix heat maps (D) can
visualize correlation strength between multiple continuous variables.
Inappropriate Choices: Pie charts (C) show proportional composition of categorical
data. Bar charts (E) compare discrete categories, not continuous relationships.
Q3: A hospital tracks daily patient census over a month. The data shows a right-skewed
distribution with a mean of 145 patients and a median of 138 patients. Which statement
best describes this distribution?
A. The mean underestimates the typical patient census
B. The presence of high census outliers is pulling the mean upward above the median
C. The distribution is symmetrical
D. The mode must be higher than the mean
Correct Answer: B
Rationale: Competency: C784 Competency 1.1: Analyze distribution shapes and their
implications for healthcare data.
,Distribution Analysis: In right-skewed distributions, the tail extends toward higher
values. The mean is sensitive to extreme values and gets pulled toward the tail, while
the median remains robust. Since mean (145) > median (138), high outliers exist.
Distractor Analysis: A is incorrect—the mean overestimates due to high outliers. C is
opposite of right-skewed. D cannot be determined; mode could be lower than both.
Q4: Calculate the interquartile range (IQR) for the following sorted data representing
patient satisfaction scores: [62, 68, 72, 75, 78, 82, 85, 88, 92, 95, 98]
A. 15
B. 20
C. 23
D. 36
Correct Answer: B
Rationale: Competency: C784 Competency 1.2: Calculate and interpret measures of
variability.
Calculation Steps:
1. Q1 (25th percentile) = median of lower half: [62, 68, 72, 75, 78] → Q1 = 72
2. Q3 (75th percentile) = median of upper half: [85, 88, 92, 95, 98] → Q3 = 92
IQR = Q3 - Q1 = 92 - 72 = 20
3. Distractor Analysis: A (15) miscalculates Q1 or Q3. C (23) uses incorrect
percentile positions. D (36) is the range (98-62), not IQR.
Q5: A quality improvement team wants to display the percentage breakdown of patient
insurance types (Medicare, Medicaid, Private, Uninsured). Which visualization is most
appropriate?
A. Histogram
B. Box plot
C. Pie chart or bar chart
D. Scatter plot
, Correct Answer: C
Rationale: Competency: C784 Competency 1.3: Select appropriate graphical displays for
categorical healthcare data.
Categorical Composition: Pie charts and bar charts effectively display proportional
breakdowns of categorical data like insurance type percentages.
Inappropriate Choices: Histograms (A) and box plots (B) display continuous data
distributions. Scatter plots (D) show relationships between continuous variables.
Q6: In a dataset of 500 patients, the mean length of stay is 4.5 days with a standard
deviation of 2.1 days. What is the z-score for a patient who stayed 8.7 days?
A. 1.5
B. 2.0
C. 2.5
D. 4.1
Correct Answer: B
Rationale: Competency: C784 Competency 1.4: Calculate and interpret standardized
scores in healthcare contexts.
Calculation: z = (X - μ) / σ = (8.7 - 4.5) / 2.1 = 4..1 = 2.0
Interpretation: This patient stayed 2 standard deviations above the mean, a statistically
unusual duration.
Distractor Analysis: A (1.5) uses incorrect numerator (3.15). C (2.5) misdivides
(5.25/2.1). D (4.1) is the actual LOS, not the z-score.
Q7: Which measure of central tendency is most appropriate for reporting typical
hospital length of stay when the data is heavily right-skewed with several extreme
outliers?
A. Mean
