WGU C784 Applied Healthcare Statistics Objective
Assessment – WGU C784 Study Guide, Original
Practice Questions & Answers, Objective Assessment
Preparation, Comprehensive Applied Healthcare
Statistics Review, Probability, Descriptive Statistics,
Regression, Correlation, Algebra, Research Design &
Healthcare Data Interpretation
Question 1: A clinical trial is testing a new drug to reduce systolic blood
pressure. The trial reports a p-value of 0.03 when comparing the treatment
group to the placebo group. Assuming a standard alpha level of 0.05, what is
the correct interpretation of this result?
A. There is a 3% probability that the null hypothesis is true.
B. The results are not statistically significant, and the null hypothesis should be retained.
C. The observed difference is statistically significant, and the null hypothesis is rejected.
D. There is a 97% probability that the new drug is effective for all patients.
CORRECT ANSWER: C. The observed difference is statistically significant, and
the null hypothesis is rejected.
Rationale: Since the p-value (0.03) is less than the alpha level (0.05), the result is
statistically significant. This leads to the rejection of the null hypothesis in favor of the
alternative. The p-value does not represent the probability that the null is true (A), nor
does it quantify the probability of effectiveness for all patients (D). Option B is incorrect
because the p-value is below the threshold for significance.
Question 2: A healthcare administrator is reviewing the length of stay (in days)
for 50 patients. The mean is 4.5 days and the median is 3.2 days. Which of the
following best describes the shape of the distribution?
A. Symmetrical
B. Negatively skewed
C. Positively skewed
D. Bimodal
CORRECT ANSWER: C. Positively skewed
Rationale: When the mean is greater than the median, the distribution is typically
positively skewed (right-skewed). This occurs because a few high values (longer stays)
pull the mean upward. A symmetrical distribution would have approximately equal mean
and median. A negative skew would have the mean less than the median.
Question 3: In a study, the correlation coefficient (r) between daily exercise
minutes and resting heart rate is -0.75. How should this correlation be
interpreted?
,A. There is a weak positive relationship between exercise and heart rate.
B. There is a strong negative relationship between exercise and heart rate.
C. There is no linear relationship between exercise and heart rate.
D. There is a moderate positive relationship between exercise and heart rate.
CORRECT ANSWER: B. There is a strong negative relationship between
exercise and heart rate.
Rationale: The correlation coefficient ranges from -1 to +1. A value of -0.75 is close to -
1, indicating a strong negative linear relationship. As exercise minutes increase, resting
heart rate tends to decrease. A is incorrect because it is negative, not positive. C is
incorrect because it is not zero. D is incorrect because the strength is strong, not
moderate.
Question 4: A nurse records the following blood glucose levels (mg/dL) for a
patient over five days: 98, 102, 95, 100, 105. What is the range of this data set?
A. 5
B. 7
C. 10
D. 100
CORRECT ANSWER: C. 10
Rationale: The range is the difference between the maximum and minimum values. The
maximum is 105 and the minimum is 95. The range is 105 - 95 = 10. The other options
are miscalculations of the range.
Question 5: A quality improvement team is analyzing the rate of hospital-
acquired infections over 12 consecutive months. Which type of chart is most
appropriate for monitoring this data over time?
A. Histogram
B. Pareto chart
C. Run chart
D. Scatterplot
CORRECT ANSWER: C. Run chart
Rationale: A run chart is a line graph that displays data points in chronological order,
making it ideal for monitoring trends and patterns over time. A histogram is used for
frequency distributions. A Pareto chart is used for prioritizing categories. A scatterplot is
used to show relationships between two variables.
,Question 6: A clinical study measures the weight of patients in kilograms.
What level of measurement is weight?
A. Nominal
B. Ordinal
C. Interval
D. Ratio
CORRECT ANSWER: D. Ratio
Rationale: Weight is a ratio level of measurement because it has a true zero point (0 kg
indicates absence of weight) and equal intervals between values. It is not nominal
(categories), ordinal (ranked order), or interval (which lacks a true zero, like temperature
in Celsius).
Question 7: A research study reports that the 95% confidence interval for the
mean reduction in pain scores is (1.2, 2.8). What is the best interpretation of
this interval?
A. 95% of all patients in the study had a pain reduction between 1.2 and 2.8.
B. The population mean reduction is exactly 2.0.
C. We are 95% confident that the true population mean reduction lies between 1.2 and
2.8.
D. There is a 95% chance that the sample mean will fall between 1.2 and 2.8.
CORRECT ANSWER: C. We are 95% confident that the true population mean
reduction lies between 1.2 and 2.8.
Rationale: A 95% confidence interval provides a range of plausible values for the true
population parameter. It does not describe individual patient scores (A), nor does it
identify a single exact point (B). It is a statement about the population mean, not the
sample mean (D).
Question 8: What is the primary purpose of using a control chart in a
healthcare setting?
A. To display the distribution of a single categorical variable.
B. To determine the strength of the relationship between two variables.
C. To distinguish between common cause and special cause variation in a process.
D. To rank causes of a problem from most to least frequent.
CORRECT ANSWER: C. To distinguish between common cause and special
cause variation in a process.
Rationale: Control charts are used in statistical process control to monitor stability and
identify variations that may require investigation. They help differentiate between
, inherent process variation (common cause) and variation due to assignable factors
(special cause). A is for frequency tables, B is for correlation, and D is for Pareto charts.
Question 9: A patient satisfaction survey uses a Likert scale from 1 (Very
Dissatisfied) to 5 (Very Satisfied). What is the median of the following
responses: 4, 5, 3, 4, 4?
A. 3
B. 4
C. 4.5
D. 5
CORRECT ANSWER: B. 4
Rationale: To find the median, first order the values: 3, 4, 4, 4, 5. The middle value (the
3rd of 5) is 4. The mean would be 4, but the median is correctly identified as 4. Option A
is the minimum, C is a miscalculation, and D is the maximum.
Question 10: A test for a disease has a sensitivity of 95% and a specificity of
80%. What does the specificity of 80% indicate?
A. 80% of people with the disease will test positive.
B. 80% of people without the disease will test negative.
C. 80% of positive test results are true positives.
D. 80% of negative test results are true negatives.
CORRECT ANSWER: B. 80% of people without the disease will test negative.
Rationale: Specificity is the proportion of true negatives correctly identified. It measures
the test's ability to correctly rule out the disease in healthy individuals. A defines
sensitivity. C defines positive predictive value. D is the complement of the false negative
rate.
Question 11: What is the interquartile range (IQR) for the following data set:
10, 12, 14, 18, 20, 22, 26?
A. 8
B. 10
C. 12
D. 16
CORRECT ANSWER: B. 10
Rationale: The IQR is Q3 - Q1. For this data set, Q1 is 12 (median of lower half: 10, 12,
14) and Q3 is 22 (median of upper half: 20, 22, 26). The IQR is 22 - 12 = 10. A is the
median, C is a miscalculation, and D is the range.
Assessment – WGU C784 Study Guide, Original
Practice Questions & Answers, Objective Assessment
Preparation, Comprehensive Applied Healthcare
Statistics Review, Probability, Descriptive Statistics,
Regression, Correlation, Algebra, Research Design &
Healthcare Data Interpretation
Question 1: A clinical trial is testing a new drug to reduce systolic blood
pressure. The trial reports a p-value of 0.03 when comparing the treatment
group to the placebo group. Assuming a standard alpha level of 0.05, what is
the correct interpretation of this result?
A. There is a 3% probability that the null hypothesis is true.
B. The results are not statistically significant, and the null hypothesis should be retained.
C. The observed difference is statistically significant, and the null hypothesis is rejected.
D. There is a 97% probability that the new drug is effective for all patients.
CORRECT ANSWER: C. The observed difference is statistically significant, and
the null hypothesis is rejected.
Rationale: Since the p-value (0.03) is less than the alpha level (0.05), the result is
statistically significant. This leads to the rejection of the null hypothesis in favor of the
alternative. The p-value does not represent the probability that the null is true (A), nor
does it quantify the probability of effectiveness for all patients (D). Option B is incorrect
because the p-value is below the threshold for significance.
Question 2: A healthcare administrator is reviewing the length of stay (in days)
for 50 patients. The mean is 4.5 days and the median is 3.2 days. Which of the
following best describes the shape of the distribution?
A. Symmetrical
B. Negatively skewed
C. Positively skewed
D. Bimodal
CORRECT ANSWER: C. Positively skewed
Rationale: When the mean is greater than the median, the distribution is typically
positively skewed (right-skewed). This occurs because a few high values (longer stays)
pull the mean upward. A symmetrical distribution would have approximately equal mean
and median. A negative skew would have the mean less than the median.
Question 3: In a study, the correlation coefficient (r) between daily exercise
minutes and resting heart rate is -0.75. How should this correlation be
interpreted?
,A. There is a weak positive relationship between exercise and heart rate.
B. There is a strong negative relationship between exercise and heart rate.
C. There is no linear relationship between exercise and heart rate.
D. There is a moderate positive relationship between exercise and heart rate.
CORRECT ANSWER: B. There is a strong negative relationship between
exercise and heart rate.
Rationale: The correlation coefficient ranges from -1 to +1. A value of -0.75 is close to -
1, indicating a strong negative linear relationship. As exercise minutes increase, resting
heart rate tends to decrease. A is incorrect because it is negative, not positive. C is
incorrect because it is not zero. D is incorrect because the strength is strong, not
moderate.
Question 4: A nurse records the following blood glucose levels (mg/dL) for a
patient over five days: 98, 102, 95, 100, 105. What is the range of this data set?
A. 5
B. 7
C. 10
D. 100
CORRECT ANSWER: C. 10
Rationale: The range is the difference between the maximum and minimum values. The
maximum is 105 and the minimum is 95. The range is 105 - 95 = 10. The other options
are miscalculations of the range.
Question 5: A quality improvement team is analyzing the rate of hospital-
acquired infections over 12 consecutive months. Which type of chart is most
appropriate for monitoring this data over time?
A. Histogram
B. Pareto chart
C. Run chart
D. Scatterplot
CORRECT ANSWER: C. Run chart
Rationale: A run chart is a line graph that displays data points in chronological order,
making it ideal for monitoring trends and patterns over time. A histogram is used for
frequency distributions. A Pareto chart is used for prioritizing categories. A scatterplot is
used to show relationships between two variables.
,Question 6: A clinical study measures the weight of patients in kilograms.
What level of measurement is weight?
A. Nominal
B. Ordinal
C. Interval
D. Ratio
CORRECT ANSWER: D. Ratio
Rationale: Weight is a ratio level of measurement because it has a true zero point (0 kg
indicates absence of weight) and equal intervals between values. It is not nominal
(categories), ordinal (ranked order), or interval (which lacks a true zero, like temperature
in Celsius).
Question 7: A research study reports that the 95% confidence interval for the
mean reduction in pain scores is (1.2, 2.8). What is the best interpretation of
this interval?
A. 95% of all patients in the study had a pain reduction between 1.2 and 2.8.
B. The population mean reduction is exactly 2.0.
C. We are 95% confident that the true population mean reduction lies between 1.2 and
2.8.
D. There is a 95% chance that the sample mean will fall between 1.2 and 2.8.
CORRECT ANSWER: C. We are 95% confident that the true population mean
reduction lies between 1.2 and 2.8.
Rationale: A 95% confidence interval provides a range of plausible values for the true
population parameter. It does not describe individual patient scores (A), nor does it
identify a single exact point (B). It is a statement about the population mean, not the
sample mean (D).
Question 8: What is the primary purpose of using a control chart in a
healthcare setting?
A. To display the distribution of a single categorical variable.
B. To determine the strength of the relationship between two variables.
C. To distinguish between common cause and special cause variation in a process.
D. To rank causes of a problem from most to least frequent.
CORRECT ANSWER: C. To distinguish between common cause and special
cause variation in a process.
Rationale: Control charts are used in statistical process control to monitor stability and
identify variations that may require investigation. They help differentiate between
, inherent process variation (common cause) and variation due to assignable factors
(special cause). A is for frequency tables, B is for correlation, and D is for Pareto charts.
Question 9: A patient satisfaction survey uses a Likert scale from 1 (Very
Dissatisfied) to 5 (Very Satisfied). What is the median of the following
responses: 4, 5, 3, 4, 4?
A. 3
B. 4
C. 4.5
D. 5
CORRECT ANSWER: B. 4
Rationale: To find the median, first order the values: 3, 4, 4, 4, 5. The middle value (the
3rd of 5) is 4. The mean would be 4, but the median is correctly identified as 4. Option A
is the minimum, C is a miscalculation, and D is the maximum.
Question 10: A test for a disease has a sensitivity of 95% and a specificity of
80%. What does the specificity of 80% indicate?
A. 80% of people with the disease will test positive.
B. 80% of people without the disease will test negative.
C. 80% of positive test results are true positives.
D. 80% of negative test results are true negatives.
CORRECT ANSWER: B. 80% of people without the disease will test negative.
Rationale: Specificity is the proportion of true negatives correctly identified. It measures
the test's ability to correctly rule out the disease in healthy individuals. A defines
sensitivity. C defines positive predictive value. D is the complement of the false negative
rate.
Question 11: What is the interquartile range (IQR) for the following data set:
10, 12, 14, 18, 20, 22, 26?
A. 8
B. 10
C. 12
D. 16
CORRECT ANSWER: B. 10
Rationale: The IQR is Q3 - Q1. For this data set, Q1 is 12 (median of lower half: 10, 12,
14) and Q3 is 22 (median of upper half: 20, 22, 26). The IQR is 22 - 12 = 10. A is the
median, C is a miscalculation, and D is the range.
