WGU C784 – Applied Healthcare Statistics | Objective Assessment Q&A
1. Which measure of central tendency is most affected by outliers?
A) Mean
B) Median
C) Mode
D) Range
Answer: A) Mean
Rationale:
The mean takes into account all values, so extreme values (outliers) can
significantly pull the mean higher or lower. The median and mode are more
resistant to outliers.
2. What type of variable is blood type (A, B, AB, O)?
A) Continuous
B) Ordinal
C) Nominal
D) Interval
Answer: C) Nominal
,Rationale:
Blood type categories have no natural order or ranking, making them nominal
(categorical) variables.
3. Which test would you use to compare the mean systolic blood pressure
between two independent groups?
A) Paired t-test
B) Independent t-test
C) Chi-square test
D) ANOVA
Answer: B) Independent t-test
Rationale:
An independent t-test compares means between two independent groups. A
paired t-test is for related samples, ANOVA is for 3 or more groups, and chi-
square is for categorical data.
4. In hypothesis testing, what does a p-value less than 0.05 indicate?
A) The null hypothesis is true
B) The null hypothesis should be rejected
C) The alternative hypothesis is false
D) There is no statistical significance
Answer: B) The null hypothesis should be rejected
Rationale:
A p-value less than 0.05 generally means the observed data is unlikely under the
null hypothesis, so we reject it in favor of the alternative.
5. What does a confidence interval (CI) represent?
A) The probability that the null hypothesis is true
B) The range within which the population parameter is expected to lie with a
,certain confidence
C) The sample mean
D) The significance level
Answer: B) The range within which the population parameter is expected to lie
with a certain confidence
Rationale:
A CI provides an estimated range of values likely to include the true population
parameter with a given confidence level (e.g., 95%).
6. What type of study design is best suited to determine the prevalence of a
disease at a single point in time?
A) Cohort study
B) Case-control study
C) Cross-sectional study
D) Randomized controlled trial
Answer: C) Cross-sectional study
Rationale:
Cross-sectional studies measure the prevalence of conditions or characteristics
at a specific point in time.
7. What is the main purpose of using logistic regression in healthcare statistics?
A) To predict continuous outcomes
B) To compare means between groups
C) To model the probability of a binary outcome
D) To measure correlation between two continuous variables
Answer: C) To model the probability of a binary outcome
Rationale:
Logistic regression is used to model outcomes that are binary (e.g., disease
present vs. absent).
, 8. Which correlation coefficient measures the strength and direction of a linear
relationship between two continuous variables?
A) Pearson’s r
B) Spearman’s rho
C) Chi-square
D) ANOVA
Answer: A) Pearson’s r
Rationale:
Pearson’s correlation measures the linear relationship between two continuous,
normally distributed variables.
9. If a study reports a relative risk (RR) of 2.0 for smoking and lung cancer, what
does this mean?
A) Smoking has no effect on lung cancer risk
B) Smokers have twice the risk of lung cancer compared to non-smokers C)
Smoking reduces lung cancer risk by half
D) Lung cancer causes smoking
Answer: B) Smokers have twice the risk of lung cancer compared to non-smokers
Rationale:
A RR of 2.0 means the exposed group (smokers) has double the risk of the
outcome (lung cancer) relative to the unexposed.
10. What is statistical power?
A) The probability of correctly rejecting a false null hypothesis
B) The chance of making a Type I error
C) The probability of accepting a false null hypothesis
D) The threshold p-value used in hypothesis testing
Answer: A) The probability of correctly rejecting a false null hypothesis
1. Which measure of central tendency is most affected by outliers?
A) Mean
B) Median
C) Mode
D) Range
Answer: A) Mean
Rationale:
The mean takes into account all values, so extreme values (outliers) can
significantly pull the mean higher or lower. The median and mode are more
resistant to outliers.
2. What type of variable is blood type (A, B, AB, O)?
A) Continuous
B) Ordinal
C) Nominal
D) Interval
Answer: C) Nominal
,Rationale:
Blood type categories have no natural order or ranking, making them nominal
(categorical) variables.
3. Which test would you use to compare the mean systolic blood pressure
between two independent groups?
A) Paired t-test
B) Independent t-test
C) Chi-square test
D) ANOVA
Answer: B) Independent t-test
Rationale:
An independent t-test compares means between two independent groups. A
paired t-test is for related samples, ANOVA is for 3 or more groups, and chi-
square is for categorical data.
4. In hypothesis testing, what does a p-value less than 0.05 indicate?
A) The null hypothesis is true
B) The null hypothesis should be rejected
C) The alternative hypothesis is false
D) There is no statistical significance
Answer: B) The null hypothesis should be rejected
Rationale:
A p-value less than 0.05 generally means the observed data is unlikely under the
null hypothesis, so we reject it in favor of the alternative.
5. What does a confidence interval (CI) represent?
A) The probability that the null hypothesis is true
B) The range within which the population parameter is expected to lie with a
,certain confidence
C) The sample mean
D) The significance level
Answer: B) The range within which the population parameter is expected to lie
with a certain confidence
Rationale:
A CI provides an estimated range of values likely to include the true population
parameter with a given confidence level (e.g., 95%).
6. What type of study design is best suited to determine the prevalence of a
disease at a single point in time?
A) Cohort study
B) Case-control study
C) Cross-sectional study
D) Randomized controlled trial
Answer: C) Cross-sectional study
Rationale:
Cross-sectional studies measure the prevalence of conditions or characteristics
at a specific point in time.
7. What is the main purpose of using logistic regression in healthcare statistics?
A) To predict continuous outcomes
B) To compare means between groups
C) To model the probability of a binary outcome
D) To measure correlation between two continuous variables
Answer: C) To model the probability of a binary outcome
Rationale:
Logistic regression is used to model outcomes that are binary (e.g., disease
present vs. absent).
, 8. Which correlation coefficient measures the strength and direction of a linear
relationship between two continuous variables?
A) Pearson’s r
B) Spearman’s rho
C) Chi-square
D) ANOVA
Answer: A) Pearson’s r
Rationale:
Pearson’s correlation measures the linear relationship between two continuous,
normally distributed variables.
9. If a study reports a relative risk (RR) of 2.0 for smoking and lung cancer, what
does this mean?
A) Smoking has no effect on lung cancer risk
B) Smokers have twice the risk of lung cancer compared to non-smokers C)
Smoking reduces lung cancer risk by half
D) Lung cancer causes smoking
Answer: B) Smokers have twice the risk of lung cancer compared to non-smokers
Rationale:
A RR of 2.0 means the exposed group (smokers) has double the risk of the
outcome (lung cancer) relative to the unexposed.
10. What is statistical power?
A) The probability of correctly rejecting a false null hypothesis
B) The chance of making a Type I error
C) The probability of accepting a false null hypothesis
D) The threshold p-value used in hypothesis testing
Answer: A) The probability of correctly rejecting a false null hypothesis
