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, Data
Interpretation & Healthcare Research
Question 1: A researcher is studying the blood glucose levels of a population of
patients with Type 2 diabetes. The mean fasting blood glucose level is 130
mg/dL with a standard deviation of 15 mg/dL. Assuming the data is normally
distributed, what is the approximate percentage of patients who have a fasting
blood glucose level between 115 mg/dL and 145 mg/dL?
A. 34%
B. 68%
C. 95%
D. 99.7%
CORRECT ANSWER: B. 68%
Rationale: In a normal distribution, approximately 68% of the data falls within ±1
standard deviation of the mean. The mean is 130, and one standard deviation is 15, so
the range is 130 ± 15 = 115 to 145.
Question 2: A hospital administrator wants to determine the most common
diagnosis code among patients admitted over the last month. Which measure
of central tendency is most appropriate for this categorical data?
A. Mean
B. Median
C. Mode
D. Standard Deviation
CORRECT ANSWER: C. Mode
Rationale: The mode is the only measure of central tendency that can be used for
categorical data. It identifies the most frequently occurring category in a dataset. The
mean and median require numerical data.
Question 3: A clinical trial tests a new painkiller. The null hypothesis states
that the drug has no effect on pain levels. The study results yield a p-value of
0.03. Assuming a significance level (alpha) of 0.05, what is the correct
decision?
A. Accept the null hypothesis
B. Fail to reject the null hypothesis
C. Reject the null hypothesis
D. Conclude the drug has no effect
,CORRECT ANSWER: C. Reject the null hypothesis
Rationale: Since the p-value (0.03) is less than the alpha level (0.05), the result is
statistically significant. We reject the null hypothesis and conclude there is evidence that
the drug has an effect.
Question 4: What is the primary purpose of descriptive statistics in healthcare
research?
A. To prove a hypothesis is true
B. To make inferences about a population from a sample
C. To summarize and organize sample data
D. To predict future patient outcomes
CORRECT ANSWER: C. To summarize and organize sample data
Rationale: Descriptive statistics are used to describe, summarize, and organize the basic
features of a dataset in a meaningful way. Inferential statistics (Option B) are used to
make predictions or inferences about a population.
Question 5: A dataset of patient ages is as follows: 34, 38, 42, 45, 52, 58, 61.
What is the median age?
A. 45
B. 46
C. 47
D. 52
CORRECT ANSWER: A. 45
Rationale: The median is the middle value in an ordered dataset. With 7 values, the 4th
value (45) is the median. There are three values below and three above.
Question 6: A study requires a sample size of 100 patients. However, the
researchers encounter a 20% dropout rate. How many patients should be
initially enrolled to ensure a final sample size of at least 100?
A. 120
B. 125
C. 130
D. 150
CORRECT ANSWER: B. 125
Rationale: To maintain a final sample of 100 with a 20% dropout, the initial enrollment
(N) must satisfy N * 0.80 = 100. Solving for N gives N = .80 = 125.
Question 7: Which measure of variability describes the average distance of
data points from the mean?
A. Range
B. Variance
,C. Standard Deviation
D. Interquartile Range
CORRECT ANSWER: C. Standard Deviation
Rationale: The standard deviation is a measure of variability that represents the average
distance of each data point from the mean. Variance is the square of the standard
deviation. Range is the difference between the maximum and minimum.
Question 8: A Chi-squared test is used to analyze the relationship between
smoking status and lung cancer incidence. The result is statistically
significant. What is the most appropriate conclusion?
A. Smoking causes lung cancer.
B. There is an association between smoking and lung cancer.
C. There is no association between smoking and lung cancer.
D. The sample size was too small.
CORRECT ANSWER: B. There is an association between smoking and lung
cancer.
Rationale: A Chi-squared test determines if there is a statistically significant association
between two categorical variables. It does not prove causation; it only establishes an
association.
Question 9: What is the primary difference between the mean and the median
in a skewed distribution?
A. There is no difference.
B. The mean is always lower.
C. The median is always higher.
D. The mean is affected more by outliers.
CORRECT ANSWER: D. The mean is affected more by outliers.
Rationale: The mean is highly sensitive to extreme values (outliers) because it
incorporates all data points in the calculation. The median is robust and resistant to
outliers, making it a better measure of center for skewed data.
Question 10: A healthcare researcher is calculating the Body Mass Index (BMI)
for a group of 50 patients. The mean BMI is 28.5 kg/m². To construct a 95%
confidence interval, what additional piece of information is most crucial?
A. The median BMI
B. The standard deviation
C. The age of the patients
D. The mode of the BMIs
CORRECT ANSWER: B. The standard deviation
, Rationale: A confidence interval requires the mean, the standard deviation (or standard
error), and the sample size (n) to calculate the margin of error.
Question 11: A pharmaceutical company is testing a new drug. They want to
ensure that the sample is representative of the general population. Which
sampling technique is best for this purpose?
A. Convenience sampling
B. Purposive sampling
C. Simple random sampling
D. Quota sampling
CORRECT ANSWER: C. Simple random sampling
Rationale: Simple random sampling gives every member of the population an equal
chance of being selected, which helps create a representative sample and reduces
selection bias. Convenience and purposive sampling introduce bias.
Question 12: A hospital reports that the average length of stay (LOS) for a
surgical procedure is 4 days. Which type of statistical measure is this?
A. Inferential statistic
B. Descriptive statistic
C. Predictive statistic
D. Qualitative statistic
CORRECT ANSWER: B. Descriptive statistic
Rationale: The average length of stay summarizes the data from the hospital’s current
patients. Since it is summarizing a sample without making predictions about a larger
population, it is a descriptive statistic.
Question 13: A new screening test for a disease has a high sensitivity. What
does this indicate?
A. The test has a low false positive rate.
B. The test has a low false negative rate.
C. The test is specific for the disease.
D. The test has a high positive predictive value.
CORRECT ANSWER: B. The test has a low false negative rate.
Rationale: Sensitivity is the probability that a test will correctly identify individuals who
have the disease (True Positives / [True Positives + False Negatives]). High sensitivity
results in fewer false negatives.
Question 14: What does a p-value of 0.001 indicate in a clinical study?
A. There is a 0.1% chance the results are due to chance.
B. The null hypothesis is definitely false.
Assessment – WGU C784 Study Guide, Original
Practice Questions & Answers, Objective Assessment
Preparation, Comprehensive Applied Healthcare
Statistics Review, Probability, Descriptive Statistics,
Regression, Correlation, Algebra, Data
Interpretation & Healthcare Research
Question 1: A researcher is studying the blood glucose levels of a population of
patients with Type 2 diabetes. The mean fasting blood glucose level is 130
mg/dL with a standard deviation of 15 mg/dL. Assuming the data is normally
distributed, what is the approximate percentage of patients who have a fasting
blood glucose level between 115 mg/dL and 145 mg/dL?
A. 34%
B. 68%
C. 95%
D. 99.7%
CORRECT ANSWER: B. 68%
Rationale: In a normal distribution, approximately 68% of the data falls within ±1
standard deviation of the mean. The mean is 130, and one standard deviation is 15, so
the range is 130 ± 15 = 115 to 145.
Question 2: A hospital administrator wants to determine the most common
diagnosis code among patients admitted over the last month. Which measure
of central tendency is most appropriate for this categorical data?
A. Mean
B. Median
C. Mode
D. Standard Deviation
CORRECT ANSWER: C. Mode
Rationale: The mode is the only measure of central tendency that can be used for
categorical data. It identifies the most frequently occurring category in a dataset. The
mean and median require numerical data.
Question 3: A clinical trial tests a new painkiller. The null hypothesis states
that the drug has no effect on pain levels. The study results yield a p-value of
0.03. Assuming a significance level (alpha) of 0.05, what is the correct
decision?
A. Accept the null hypothesis
B. Fail to reject the null hypothesis
C. Reject the null hypothesis
D. Conclude the drug has no effect
,CORRECT ANSWER: C. Reject the null hypothesis
Rationale: Since the p-value (0.03) is less than the alpha level (0.05), the result is
statistically significant. We reject the null hypothesis and conclude there is evidence that
the drug has an effect.
Question 4: What is the primary purpose of descriptive statistics in healthcare
research?
A. To prove a hypothesis is true
B. To make inferences about a population from a sample
C. To summarize and organize sample data
D. To predict future patient outcomes
CORRECT ANSWER: C. To summarize and organize sample data
Rationale: Descriptive statistics are used to describe, summarize, and organize the basic
features of a dataset in a meaningful way. Inferential statistics (Option B) are used to
make predictions or inferences about a population.
Question 5: A dataset of patient ages is as follows: 34, 38, 42, 45, 52, 58, 61.
What is the median age?
A. 45
B. 46
C. 47
D. 52
CORRECT ANSWER: A. 45
Rationale: The median is the middle value in an ordered dataset. With 7 values, the 4th
value (45) is the median. There are three values below and three above.
Question 6: A study requires a sample size of 100 patients. However, the
researchers encounter a 20% dropout rate. How many patients should be
initially enrolled to ensure a final sample size of at least 100?
A. 120
B. 125
C. 130
D. 150
CORRECT ANSWER: B. 125
Rationale: To maintain a final sample of 100 with a 20% dropout, the initial enrollment
(N) must satisfy N * 0.80 = 100. Solving for N gives N = .80 = 125.
Question 7: Which measure of variability describes the average distance of
data points from the mean?
A. Range
B. Variance
,C. Standard Deviation
D. Interquartile Range
CORRECT ANSWER: C. Standard Deviation
Rationale: The standard deviation is a measure of variability that represents the average
distance of each data point from the mean. Variance is the square of the standard
deviation. Range is the difference between the maximum and minimum.
Question 8: A Chi-squared test is used to analyze the relationship between
smoking status and lung cancer incidence. The result is statistically
significant. What is the most appropriate conclusion?
A. Smoking causes lung cancer.
B. There is an association between smoking and lung cancer.
C. There is no association between smoking and lung cancer.
D. The sample size was too small.
CORRECT ANSWER: B. There is an association between smoking and lung
cancer.
Rationale: A Chi-squared test determines if there is a statistically significant association
between two categorical variables. It does not prove causation; it only establishes an
association.
Question 9: What is the primary difference between the mean and the median
in a skewed distribution?
A. There is no difference.
B. The mean is always lower.
C. The median is always higher.
D. The mean is affected more by outliers.
CORRECT ANSWER: D. The mean is affected more by outliers.
Rationale: The mean is highly sensitive to extreme values (outliers) because it
incorporates all data points in the calculation. The median is robust and resistant to
outliers, making it a better measure of center for skewed data.
Question 10: A healthcare researcher is calculating the Body Mass Index (BMI)
for a group of 50 patients. The mean BMI is 28.5 kg/m². To construct a 95%
confidence interval, what additional piece of information is most crucial?
A. The median BMI
B. The standard deviation
C. The age of the patients
D. The mode of the BMIs
CORRECT ANSWER: B. The standard deviation
, Rationale: A confidence interval requires the mean, the standard deviation (or standard
error), and the sample size (n) to calculate the margin of error.
Question 11: A pharmaceutical company is testing a new drug. They want to
ensure that the sample is representative of the general population. Which
sampling technique is best for this purpose?
A. Convenience sampling
B. Purposive sampling
C. Simple random sampling
D. Quota sampling
CORRECT ANSWER: C. Simple random sampling
Rationale: Simple random sampling gives every member of the population an equal
chance of being selected, which helps create a representative sample and reduces
selection bias. Convenience and purposive sampling introduce bias.
Question 12: A hospital reports that the average length of stay (LOS) for a
surgical procedure is 4 days. Which type of statistical measure is this?
A. Inferential statistic
B. Descriptive statistic
C. Predictive statistic
D. Qualitative statistic
CORRECT ANSWER: B. Descriptive statistic
Rationale: The average length of stay summarizes the data from the hospital’s current
patients. Since it is summarizing a sample without making predictions about a larger
population, it is a descriptive statistic.
Question 13: A new screening test for a disease has a high sensitivity. What
does this indicate?
A. The test has a low false positive rate.
B. The test has a low false negative rate.
C. The test is specific for the disease.
D. The test has a high positive predictive value.
CORRECT ANSWER: B. The test has a low false negative rate.
Rationale: Sensitivity is the probability that a test will correctly identify individuals who
have the disease (True Positives / [True Positives + False Negatives]). High sensitivity
results in fewer false negatives.
Question 14: What does a p-value of 0.001 indicate in a clinical study?
A. There is a 0.1% chance the results are due to chance.
B. The null hypothesis is definitely false.
