WGU C784 Applied Healthcare Statistics Objective
Assessment – C784 Study Guide, Original Practice
Questions & Answers, Objective Assessment
Preparation, Comprehensive WGU Statistics Review,
Probability, Descriptive Statistics, Regression,
Correlation, Algebra, Data Interpretation &
Healthcare Statistics
Question 1: A researcher is studying the average systolic blood pressure of a
population. The mean is 120 mmHg with a standard deviation of 15 mmHg.
Assuming a normal distribution, what is the approximate percentage of
individuals with a systolic blood pressure between 90 and 150 mmHg?
A. 68%
B. 75%
C. 95%
D. 99.7%
CORRECT ANSWER: C. 95%
Rationale: In a normal distribution, approximately 95% of the data falls within two
standard deviations of the mean. Here, 90 is (120-30) and 150 is (120+30), which is
exactly 2 standard deviations from the mean.
Question 2: A healthcare administrator is looking at the distribution of patient
wait times in the emergency room. The data is heavily skewed to the right.
Which measure of central tendency is most appropriate to report?
A. Mean
B. Median
C. Mode
D. Range
CORRECT ANSWER: B. Median
Rationale: For skewed distributions, the median is the most appropriate measure of
central tendency because it is not influenced by extreme outliers, unlike the mean which
is pulled in the direction of the skew.
Question 3: A study tests a new drug for reducing cholesterol. The null
hypothesis is that the drug has no effect. The test results yield a p-value of
0.03. Using an alpha of 0.05, what is the correct conclusion?
A. Accept the null hypothesis.
B. Reject the null hypothesis.
,C. Fail to reject the null hypothesis.
D. Conclude the drug lowers cholesterol by 3%.
CORRECT ANSWER: B. Reject the null hypothesis.
Rationale: Since the p-value (0.03) is less than the significance level (0.05), there is
sufficient evidence to reject the null hypothesis and conclude that the drug has a
statistically significant effect.
Question 4: A frequency table shows that 15 out of 50 patients have diabetes.
What is the relative frequency of patients with diabetes?
A. 0.15
B. 0.30
C. 1.50
D. 3.00
CORRECT ANSWER: B. 0.30
Rationale: Relative frequency is calculated by dividing the frequency of the event (15) by
the total number of observations (50). 15/50 = 0.30.
Question 5: Which of the following is an example of a continuous variable in a
healthcare setting?
A. Number of hospital beds
B. Number of children in a family
C. Blood glucose level
D. Number of surgical procedures
CORRECT ANSWER: C. Blood glucose level
Rationale: A continuous variable can take on any value within a range (e.g., 105.5
mg/dL). The number of beds, children, and procedures are discrete variables that can
only be whole numbers.
Question 6: A researcher calculates a 95% confidence interval for the average
BMI of a population as (26.5, 30.1). What is the best interpretation of this
interval?
A. 95% of the population's BMI falls between 26.5 and 30.1.
B. There is a 95% probability that the true population mean BMI is between 26.5 and
30.1.
C. We are 95% confident that the true population mean BMI lies between 26.5 and 30.1.
D. 95% of the sample means will fall between 26.5 and 30.1.
,CORRECT ANSWER: C. We are 95% confident that the true population mean
BMI lies between 26.5 and 30.1.
Rationale: A confidence interval provides a range of plausible values for the population
parameter based on the sample data. It reflects our confidence in the estimation
process, not the probability of the parameter itself.
Question 7: In a clinical trial, researchers want to compare the means of two
independent groups. Which statistical test is most appropriate?
A. Paired t-test
B. Independent t-test
C. Chi-square test
D. ANOVA
CORRECT ANSWER: B. Independent t-test
Rationale: An independent t-test is used to compare the means of two distinct,
independent groups. A paired t-test is for matched pairs, and ANOVA is for three or
more groups.
Question 8: A hospital records the number of patients admitted each day for a
week: 25, 30, 35, 30, 28, 32, 30. What is the mode of this dataset?
A. 28
B. 29
C. 30
D. 35
CORRECT ANSWER: C. 30
Rationale: The mode is the value that appears most frequently. In this dataset, 30
appears three times, which is more than any other value.
Question 9: What is the primary purpose of using a random sample in a
healthcare study?
A. To ensure the study is cheap.
B. To reduce measurement error.
C. To ensure the sample is representative of the population.
D. To guarantee the results are correct.
CORRECT ANSWER: C. To ensure the sample is representative of the
population.
, Rationale: Random sampling helps to minimize selection bias and ensures that the
sample is representative of the population, allowing for the generalization of results.
Question 10: A clinical trial has a very small p-value (0.001). This indicates
that:
A. The results are clinically significant.
B. The null hypothesis is likely true.
C. The results are statistically significant.
D. The sample size was too small.
CORRECT ANSWER: C. The results are statistically significant.
Rationale: A very small p-value indicates that it is very unlikely to observe such results if
the null hypothesis were true, leading to statistical significance. It does not measure
clinical significance.
Question 11: Which measure of variability is most affected by extreme outliers
in a dataset?
A. Range
B. Interquartile Range (IQR)
C. Variance
D. Standard Deviation
CORRECT ANSWER: A. Range
Rationale: The range is calculated by subtracting the minimum from the maximum
value. Since it relies solely on the extremes, it is highly sensitive to outliers.
Question 12: A graph shows the frequency distribution of patient ages. The
bars are touching each other. What type of graph is this?
A. Bar chart
B. Histogram
C. Pie chart
D. Scatter plot
CORRECT ANSWER: B. Histogram
Rationale: Histograms are used for continuous data (like age) and have touching bars,
whereas bar charts (for categorical data) have spaces between the bars.
Question 13: In a positive correlation between hours of exercise and patient
well-being scores, as hours of exercise increase:
Assessment – C784 Study Guide, Original Practice
Questions & Answers, Objective Assessment
Preparation, Comprehensive WGU Statistics Review,
Probability, Descriptive Statistics, Regression,
Correlation, Algebra, Data Interpretation &
Healthcare Statistics
Question 1: A researcher is studying the average systolic blood pressure of a
population. The mean is 120 mmHg with a standard deviation of 15 mmHg.
Assuming a normal distribution, what is the approximate percentage of
individuals with a systolic blood pressure between 90 and 150 mmHg?
A. 68%
B. 75%
C. 95%
D. 99.7%
CORRECT ANSWER: C. 95%
Rationale: In a normal distribution, approximately 95% of the data falls within two
standard deviations of the mean. Here, 90 is (120-30) and 150 is (120+30), which is
exactly 2 standard deviations from the mean.
Question 2: A healthcare administrator is looking at the distribution of patient
wait times in the emergency room. The data is heavily skewed to the right.
Which measure of central tendency is most appropriate to report?
A. Mean
B. Median
C. Mode
D. Range
CORRECT ANSWER: B. Median
Rationale: For skewed distributions, the median is the most appropriate measure of
central tendency because it is not influenced by extreme outliers, unlike the mean which
is pulled in the direction of the skew.
Question 3: A study tests a new drug for reducing cholesterol. The null
hypothesis is that the drug has no effect. The test results yield a p-value of
0.03. Using an alpha of 0.05, what is the correct conclusion?
A. Accept the null hypothesis.
B. Reject the null hypothesis.
,C. Fail to reject the null hypothesis.
D. Conclude the drug lowers cholesterol by 3%.
CORRECT ANSWER: B. Reject the null hypothesis.
Rationale: Since the p-value (0.03) is less than the significance level (0.05), there is
sufficient evidence to reject the null hypothesis and conclude that the drug has a
statistically significant effect.
Question 4: A frequency table shows that 15 out of 50 patients have diabetes.
What is the relative frequency of patients with diabetes?
A. 0.15
B. 0.30
C. 1.50
D. 3.00
CORRECT ANSWER: B. 0.30
Rationale: Relative frequency is calculated by dividing the frequency of the event (15) by
the total number of observations (50). 15/50 = 0.30.
Question 5: Which of the following is an example of a continuous variable in a
healthcare setting?
A. Number of hospital beds
B. Number of children in a family
C. Blood glucose level
D. Number of surgical procedures
CORRECT ANSWER: C. Blood glucose level
Rationale: A continuous variable can take on any value within a range (e.g., 105.5
mg/dL). The number of beds, children, and procedures are discrete variables that can
only be whole numbers.
Question 6: A researcher calculates a 95% confidence interval for the average
BMI of a population as (26.5, 30.1). What is the best interpretation of this
interval?
A. 95% of the population's BMI falls between 26.5 and 30.1.
B. There is a 95% probability that the true population mean BMI is between 26.5 and
30.1.
C. We are 95% confident that the true population mean BMI lies between 26.5 and 30.1.
D. 95% of the sample means will fall between 26.5 and 30.1.
,CORRECT ANSWER: C. We are 95% confident that the true population mean
BMI lies between 26.5 and 30.1.
Rationale: A confidence interval provides a range of plausible values for the population
parameter based on the sample data. It reflects our confidence in the estimation
process, not the probability of the parameter itself.
Question 7: In a clinical trial, researchers want to compare the means of two
independent groups. Which statistical test is most appropriate?
A. Paired t-test
B. Independent t-test
C. Chi-square test
D. ANOVA
CORRECT ANSWER: B. Independent t-test
Rationale: An independent t-test is used to compare the means of two distinct,
independent groups. A paired t-test is for matched pairs, and ANOVA is for three or
more groups.
Question 8: A hospital records the number of patients admitted each day for a
week: 25, 30, 35, 30, 28, 32, 30. What is the mode of this dataset?
A. 28
B. 29
C. 30
D. 35
CORRECT ANSWER: C. 30
Rationale: The mode is the value that appears most frequently. In this dataset, 30
appears three times, which is more than any other value.
Question 9: What is the primary purpose of using a random sample in a
healthcare study?
A. To ensure the study is cheap.
B. To reduce measurement error.
C. To ensure the sample is representative of the population.
D. To guarantee the results are correct.
CORRECT ANSWER: C. To ensure the sample is representative of the
population.
, Rationale: Random sampling helps to minimize selection bias and ensures that the
sample is representative of the population, allowing for the generalization of results.
Question 10: A clinical trial has a very small p-value (0.001). This indicates
that:
A. The results are clinically significant.
B. The null hypothesis is likely true.
C. The results are statistically significant.
D. The sample size was too small.
CORRECT ANSWER: C. The results are statistically significant.
Rationale: A very small p-value indicates that it is very unlikely to observe such results if
the null hypothesis were true, leading to statistical significance. It does not measure
clinical significance.
Question 11: Which measure of variability is most affected by extreme outliers
in a dataset?
A. Range
B. Interquartile Range (IQR)
C. Variance
D. Standard Deviation
CORRECT ANSWER: A. Range
Rationale: The range is calculated by subtracting the minimum from the maximum
value. Since it relies solely on the extremes, it is highly sensitive to outliers.
Question 12: A graph shows the frequency distribution of patient ages. The
bars are touching each other. What type of graph is this?
A. Bar chart
B. Histogram
C. Pie chart
D. Scatter plot
CORRECT ANSWER: B. Histogram
Rationale: Histograms are used for continuous data (like age) and have touching bars,
whereas bar charts (for categorical data) have spaces between the bars.
Question 13: In a positive correlation between hours of exercise and patient
well-being scores, as hours of exercise increase:
