WGU C784 APPLIED HEALTHCARE STATISTICS OBJECTIVE ASSESSMENT AND PRE-
ASSESSMENT ACTUAL EXAM 150 QUESTIONS AND CORRECT ANSWERS WITH
RATONALES| ALL YOU NEED TO PASS C784 EXAM
1. Which measure of central tendency is most affected by extreme values?
A) Mean ✓
B) Median
C) Mode
D) Range
Rationale: The mean includes all values in its calculation, so extreme values (outliers) heavily influence
it.
2. If a dataset has a normal distribution, approximately what percent of values lie within one standard
deviation of the mean?
A) 50%
B) 68% ✓
C) 95%
D) 99%
Rationale: In a normal distribution, ~68% of values fall within ±1 standard deviation from the mean.
3. A hospital wants to know if a new protocol reduces patient wait time. Which statistical test is most
appropriate for comparing two independent groups?
A) Paired t-test
B) Independent t-test ✓
C) Chi-square test
D) ANOVA
Rationale: Independent t-test compares the means of two independent groups.
4. Which type of data is represented by categories without a natural order?
A) Nominal ✓
B) Ordinal
C) Interval
D) Ratio
Rationale: Nominal data are categorical with no order (e.g., blood type, gender).
,5. A correlation coefficient (r) of -0.85 indicates:
A) Weak positive correlation
B) Strong negative correlation ✓
C) No correlation
D) Strong positive correlation
Rationale: The negative sign indicates inverse relationship; magnitude 0.85 indicates strong correlation.
6. Which of the following describes the probability of making a Type I error?
A) β
B) α ✓
C) p-value
D) Confidence interval
Rationale: α represents the probability of rejecting the null hypothesis when it is true.
7. A dataset has the following values: 3, 5, 7, 9, 11. What is the median?
A) 5
B) 7 ✓
C) 6
D) 9
Rationale: Median is the middle value in a sorted dataset.
8. In a study, a p-value of 0.03 indicates:
A) Strong evidence against null hypothesis ✓
B) Weak evidence against null hypothesis
C) No evidence against null hypothesis
D) Null hypothesis is true
Rationale: p < 0.05 typically indicates statistical significance, providing evidence to reject null
hypothesis.
9. The standard deviation measures:
A) Average value
B) Spread or variability of data ✓
C) Probability
D) Sample size
Rationale: Standard deviation quantifies how much values deviate from the mean.
,10. If you divide the variance by the mean, you get:
A) Standard deviation
B) Coefficient of variation ✓
C) Range
D) Median
Rationale: Coefficient of variation = SD / mean; it is a normalized measure of dispersion.
11. Which graph is most appropriate for displaying the distribution of a categorical variable?
A) Histogram
B) Bar chart ✓
C) Scatter plot
D) Boxplot
Rationale: Bar charts display frequencies of categorical data.
12. Which measure of central tendency is best for skewed data?
A) Mean
B) Median ✓
C) Mode
D) Range
Rationale: Median is resistant to outliers and skewed distributions.
13. A chi-square test is used to:
A) Compare two means
B) Compare frequencies of categorical data ✓
C) Measure correlation
D) Calculate standard deviation
Rationale: Chi-square test evaluates association between categorical variables.
14. In hypothesis testing, the null hypothesis states:
A) There is no effect or difference ✓
B) There is an effect
C) The p-value is significant
D) The sample is biased
Rationale: Null hypothesis assumes no relationship or effect.
, 15. Which of the following is an example of ratio data?
A) Temperature in Celsius
B) Number of patients admitted ✓
C) Blood type
D) Pain scale (1–5)
Rationale: Ratio data have true zero and allow for ratios (e.g., 10 patients is twice as many as 5).
16. A healthcare researcher wants to predict patient length of stay based on age and comorbidities.
Which statistical method is appropriate?
A) Logistic regression
B) Multiple linear regression ✓
C) ANOVA
D) Chi-square test
Rationale: Multiple linear regression predicts continuous outcome using multiple predictors.
17. The interquartile range (IQR) measures:
A) Total range of data
B) Spread of the middle 50% ✓
C) Mean
D) Standard deviation
Rationale: IQR = Q3 – Q1, describing variability of the central 50% of values.
18. In probability, mutually exclusive events:
A) Can occur at the same time
B) Cannot occur at the same time ✓
C) Have probability > 1
D) Are independent
Rationale: Mutually exclusive events cannot happen simultaneously.
19. If a sample mean is 50, population mean is 55, and SD is 10, what is the z-score for the sample
mean?
A) -0.5 ✓
B) 0.5
C) -5
D) 5
Rationale: Z = (X - μ) / SD = (50 - 55)/10 = -0.5.
ASSESSMENT ACTUAL EXAM 150 QUESTIONS AND CORRECT ANSWERS WITH
RATONALES| ALL YOU NEED TO PASS C784 EXAM
1. Which measure of central tendency is most affected by extreme values?
A) Mean ✓
B) Median
C) Mode
D) Range
Rationale: The mean includes all values in its calculation, so extreme values (outliers) heavily influence
it.
2. If a dataset has a normal distribution, approximately what percent of values lie within one standard
deviation of the mean?
A) 50%
B) 68% ✓
C) 95%
D) 99%
Rationale: In a normal distribution, ~68% of values fall within ±1 standard deviation from the mean.
3. A hospital wants to know if a new protocol reduces patient wait time. Which statistical test is most
appropriate for comparing two independent groups?
A) Paired t-test
B) Independent t-test ✓
C) Chi-square test
D) ANOVA
Rationale: Independent t-test compares the means of two independent groups.
4. Which type of data is represented by categories without a natural order?
A) Nominal ✓
B) Ordinal
C) Interval
D) Ratio
Rationale: Nominal data are categorical with no order (e.g., blood type, gender).
,5. A correlation coefficient (r) of -0.85 indicates:
A) Weak positive correlation
B) Strong negative correlation ✓
C) No correlation
D) Strong positive correlation
Rationale: The negative sign indicates inverse relationship; magnitude 0.85 indicates strong correlation.
6. Which of the following describes the probability of making a Type I error?
A) β
B) α ✓
C) p-value
D) Confidence interval
Rationale: α represents the probability of rejecting the null hypothesis when it is true.
7. A dataset has the following values: 3, 5, 7, 9, 11. What is the median?
A) 5
B) 7 ✓
C) 6
D) 9
Rationale: Median is the middle value in a sorted dataset.
8. In a study, a p-value of 0.03 indicates:
A) Strong evidence against null hypothesis ✓
B) Weak evidence against null hypothesis
C) No evidence against null hypothesis
D) Null hypothesis is true
Rationale: p < 0.05 typically indicates statistical significance, providing evidence to reject null
hypothesis.
9. The standard deviation measures:
A) Average value
B) Spread or variability of data ✓
C) Probability
D) Sample size
Rationale: Standard deviation quantifies how much values deviate from the mean.
,10. If you divide the variance by the mean, you get:
A) Standard deviation
B) Coefficient of variation ✓
C) Range
D) Median
Rationale: Coefficient of variation = SD / mean; it is a normalized measure of dispersion.
11. Which graph is most appropriate for displaying the distribution of a categorical variable?
A) Histogram
B) Bar chart ✓
C) Scatter plot
D) Boxplot
Rationale: Bar charts display frequencies of categorical data.
12. Which measure of central tendency is best for skewed data?
A) Mean
B) Median ✓
C) Mode
D) Range
Rationale: Median is resistant to outliers and skewed distributions.
13. A chi-square test is used to:
A) Compare two means
B) Compare frequencies of categorical data ✓
C) Measure correlation
D) Calculate standard deviation
Rationale: Chi-square test evaluates association between categorical variables.
14. In hypothesis testing, the null hypothesis states:
A) There is no effect or difference ✓
B) There is an effect
C) The p-value is significant
D) The sample is biased
Rationale: Null hypothesis assumes no relationship or effect.
, 15. Which of the following is an example of ratio data?
A) Temperature in Celsius
B) Number of patients admitted ✓
C) Blood type
D) Pain scale (1–5)
Rationale: Ratio data have true zero and allow for ratios (e.g., 10 patients is twice as many as 5).
16. A healthcare researcher wants to predict patient length of stay based on age and comorbidities.
Which statistical method is appropriate?
A) Logistic regression
B) Multiple linear regression ✓
C) ANOVA
D) Chi-square test
Rationale: Multiple linear regression predicts continuous outcome using multiple predictors.
17. The interquartile range (IQR) measures:
A) Total range of data
B) Spread of the middle 50% ✓
C) Mean
D) Standard deviation
Rationale: IQR = Q3 – Q1, describing variability of the central 50% of values.
18. In probability, mutually exclusive events:
A) Can occur at the same time
B) Cannot occur at the same time ✓
C) Have probability > 1
D) Are independent
Rationale: Mutually exclusive events cannot happen simultaneously.
19. If a sample mean is 50, population mean is 55, and SD is 10, what is the z-score for the sample
mean?
A) -0.5 ✓
B) 0.5
C) -5
D) 5
Rationale: Z = (X - μ) / SD = (50 - 55)/10 = -0.5.
