CPH CERTIFIED IN PUBLIC HEALTH EXAM
Comprehensive Practice Examination – 2026/2027 Edition
Aligned with the NBPHE CPH Examination Blueprint & Core Public Health Competencies
135 Questions | 8 Content Domains | Multiple Choice (A–D)
Contents
Section 1: Biostatistics – Study Design, Data Analysis, Interpretation (20 questions)
Section 2: Epidemiology – Disease Distribution, Risk Factors, Outbreaks (20 questions)
Section 3: Environmental Health – Risks, Toxicology, Assessment (15 questions)
Section 4: Health Policy & Management – Policy, Planning, Evaluation (20 questions)
Section 5: Social & Behavioral Sciences – Theories, Cultural Competency, Community (15 questions)
Section 6: Program Planning, Implementation & Evaluation – Models, Methods (15 questions)
Section 7: Ethics, Leadership & Interprofessional Practice (15 questions)
Section 8: Integrated Public Health Scenarios – Complex Cases (15 questions)
How to use this exam: Work through each section sequentially. One answer choice per question is correct; the correct answer
and a rationale follow each question. Use the rationales to reinforce core concepts. A reference answer key is provided on the
final page.
CPH Certified in Public Health Exam – Comprehensive Practice (2026/2027 Edition) Page 1
, Section 1 Biostatistics – Study Design, Data Analysis, Interpretation
Q1: A public health researcher analyzes annual household income in a county where a small number of
residents have extremely high incomes, producing a right-skewed distribution. Which measure of central
tendency is most appropriate for summarizing these data?
A. Mean
B. Mode
C. Median [CORRECT]
D. Range
Correct Answer: C
Rationale: The median is resistant to outliers and best represents the center of skewed data. The mean is pulled toward
extreme values, and the range is a measure of spread, not central tendency.
Q2: The ages of seven participants at a vaccination clinic are 2, 5, 6, 9, 11, 13, and 17 years. What is the
median age?
A. 9 years [CORRECT]
B. 6 years
C. 11 years
D. 13 years
Correct Answer: A
Rationale: With seven ordered values, the median is the fourth (middle) value, which is 9. The other options are the
second, fifth, and sixth values, respectively.
Q3: Which statement best distinguishes the standard error of the mean (SEM) from the standard deviation
(SD)?
A. The SEM describes the spread of individual observations in the sample.
B. The SEM is always larger than the SD.
C. The SEM estimates the variability of the sample mean across repeated samples and decreases as
sample size increases. [CORRECT]
D. The SEM is unaffected by sample size.
Correct Answer: C
Rationale: The SEM equals SD divided by the square root of n, so it quantifies the precision of the sample mean and
shrinks as the sample grows. The SD describes individual variability and does not depend on sample size.
Q4: A randomized trial comparing a new intervention with usual care reports p = 0.03. What is the correct
interpretation of this p-value?
A. If the null hypothesis were true, the probability of observing a result at least this extreme is 3%.
[CORRECT]
B. There is a 3% probability that the null hypothesis is true.
C. The intervention has a 3% chance of being ineffective.
D. There is a 97% probability that the results are due to chance.
Correct Answer: A
Rationale: The p-value is the probability of obtaining results at least as extreme as observed, assuming the null
hypothesis is true. It is not the probability that the null hypothesis is true or false.
CPH Certified in Public Health Exam – Comprehensive Practice (2026/2027 Edition) Page 2
, Q5: A health department concludes that a new outreach program increases cancer screening rates when in
fact the program has no effect. This is an example of a:
A. Type II error
B. Correct decision
C. Selection bias
D. Type I error [CORRECT]
Correct Answer: D
Rationale: Rejecting a true null hypothesis (concluding an effect exists when none does) is a Type I error. A Type II error
is failing to detect a true effect.
Q6: A study fails to detect a real association between air pollution and asthma because the sample size is
too small. This describes a:
A. Type I error
B. Type II error [CORRECT]
C. Confounding
D. Effect modification
Correct Answer: B
Rationale: Failing to reject a false null hypothesis (missing a real effect) is a Type II error, often caused by insufficient
power. Confounding and effect modification are systematic, not random, errors.
Q7: A 95% confidence interval for the mean difference in systolic blood pressure between two groups is
−4.2 to +1.8 mmHg. The best interpretation is:
A. There is a 95% chance the true difference lies within this interval.
B. The result is statistically significant because most of the interval is negative.
C. Because the interval includes 0, the difference is not statistically significant at the 0.05 level.
[CORRECT]
D. The interval is too narrow to draw any conclusions.
Correct Answer: C
Rationale: A confidence interval that contains the null value (0 for a difference) indicates the result is not statistically
significant at the corresponding alpha level. The interval is a range estimate, not a probability statement about a specific
value.
Q8: A cohort study reports a relative risk of 1.6 with a 95% confidence interval of 0.9 to 2.8. What is the
appropriate conclusion?
A. The exposure significantly increases risk.
B. The exposure significantly decreases risk.
C. The wide interval proves the study is invalid.
D. The association is not statistically significant because the confidence interval includes 1. [CORRECT]
Correct Answer: D
Rationale: For ratio measures, the null value is 1. Because the 95% CI includes 1, the association is not statistically
significant at the 0.05 level, regardless of the point estimate.
Q9: A researcher compares mean body mass index (BMI) between two independent groups: an
intervention group and a control group. The most appropriate statistical test is the:
A. Independent samples t-test [CORRECT]
B. Paired t-test
C. Chi-square test
D. One-way ANOVA
Correct Answer: A
Rationale: An independent samples t-test compares the means of two unrelated groups. A paired t-test is for matched or
repeated measures, chi-square is for categorical data, and ANOVA is for three or more groups.
CPH Certified in Public Health Exam – Comprehensive Practice (2026/2027 Edition) Page 3
Comprehensive Practice Examination – 2026/2027 Edition
Aligned with the NBPHE CPH Examination Blueprint & Core Public Health Competencies
135 Questions | 8 Content Domains | Multiple Choice (A–D)
Contents
Section 1: Biostatistics – Study Design, Data Analysis, Interpretation (20 questions)
Section 2: Epidemiology – Disease Distribution, Risk Factors, Outbreaks (20 questions)
Section 3: Environmental Health – Risks, Toxicology, Assessment (15 questions)
Section 4: Health Policy & Management – Policy, Planning, Evaluation (20 questions)
Section 5: Social & Behavioral Sciences – Theories, Cultural Competency, Community (15 questions)
Section 6: Program Planning, Implementation & Evaluation – Models, Methods (15 questions)
Section 7: Ethics, Leadership & Interprofessional Practice (15 questions)
Section 8: Integrated Public Health Scenarios – Complex Cases (15 questions)
How to use this exam: Work through each section sequentially. One answer choice per question is correct; the correct answer
and a rationale follow each question. Use the rationales to reinforce core concepts. A reference answer key is provided on the
final page.
CPH Certified in Public Health Exam – Comprehensive Practice (2026/2027 Edition) Page 1
, Section 1 Biostatistics – Study Design, Data Analysis, Interpretation
Q1: A public health researcher analyzes annual household income in a county where a small number of
residents have extremely high incomes, producing a right-skewed distribution. Which measure of central
tendency is most appropriate for summarizing these data?
A. Mean
B. Mode
C. Median [CORRECT]
D. Range
Correct Answer: C
Rationale: The median is resistant to outliers and best represents the center of skewed data. The mean is pulled toward
extreme values, and the range is a measure of spread, not central tendency.
Q2: The ages of seven participants at a vaccination clinic are 2, 5, 6, 9, 11, 13, and 17 years. What is the
median age?
A. 9 years [CORRECT]
B. 6 years
C. 11 years
D. 13 years
Correct Answer: A
Rationale: With seven ordered values, the median is the fourth (middle) value, which is 9. The other options are the
second, fifth, and sixth values, respectively.
Q3: Which statement best distinguishes the standard error of the mean (SEM) from the standard deviation
(SD)?
A. The SEM describes the spread of individual observations in the sample.
B. The SEM is always larger than the SD.
C. The SEM estimates the variability of the sample mean across repeated samples and decreases as
sample size increases. [CORRECT]
D. The SEM is unaffected by sample size.
Correct Answer: C
Rationale: The SEM equals SD divided by the square root of n, so it quantifies the precision of the sample mean and
shrinks as the sample grows. The SD describes individual variability and does not depend on sample size.
Q4: A randomized trial comparing a new intervention with usual care reports p = 0.03. What is the correct
interpretation of this p-value?
A. If the null hypothesis were true, the probability of observing a result at least this extreme is 3%.
[CORRECT]
B. There is a 3% probability that the null hypothesis is true.
C. The intervention has a 3% chance of being ineffective.
D. There is a 97% probability that the results are due to chance.
Correct Answer: A
Rationale: The p-value is the probability of obtaining results at least as extreme as observed, assuming the null
hypothesis is true. It is not the probability that the null hypothesis is true or false.
CPH Certified in Public Health Exam – Comprehensive Practice (2026/2027 Edition) Page 2
, Q5: A health department concludes that a new outreach program increases cancer screening rates when in
fact the program has no effect. This is an example of a:
A. Type II error
B. Correct decision
C. Selection bias
D. Type I error [CORRECT]
Correct Answer: D
Rationale: Rejecting a true null hypothesis (concluding an effect exists when none does) is a Type I error. A Type II error
is failing to detect a true effect.
Q6: A study fails to detect a real association between air pollution and asthma because the sample size is
too small. This describes a:
A. Type I error
B. Type II error [CORRECT]
C. Confounding
D. Effect modification
Correct Answer: B
Rationale: Failing to reject a false null hypothesis (missing a real effect) is a Type II error, often caused by insufficient
power. Confounding and effect modification are systematic, not random, errors.
Q7: A 95% confidence interval for the mean difference in systolic blood pressure between two groups is
−4.2 to +1.8 mmHg. The best interpretation is:
A. There is a 95% chance the true difference lies within this interval.
B. The result is statistically significant because most of the interval is negative.
C. Because the interval includes 0, the difference is not statistically significant at the 0.05 level.
[CORRECT]
D. The interval is too narrow to draw any conclusions.
Correct Answer: C
Rationale: A confidence interval that contains the null value (0 for a difference) indicates the result is not statistically
significant at the corresponding alpha level. The interval is a range estimate, not a probability statement about a specific
value.
Q8: A cohort study reports a relative risk of 1.6 with a 95% confidence interval of 0.9 to 2.8. What is the
appropriate conclusion?
A. The exposure significantly increases risk.
B. The exposure significantly decreases risk.
C. The wide interval proves the study is invalid.
D. The association is not statistically significant because the confidence interval includes 1. [CORRECT]
Correct Answer: D
Rationale: For ratio measures, the null value is 1. Because the 95% CI includes 1, the association is not statistically
significant at the 0.05 level, regardless of the point estimate.
Q9: A researcher compares mean body mass index (BMI) between two independent groups: an
intervention group and a control group. The most appropriate statistical test is the:
A. Independent samples t-test [CORRECT]
B. Paired t-test
C. Chi-square test
D. One-way ANOVA
Correct Answer: A
Rationale: An independent samples t-test compares the means of two unrelated groups. A paired t-test is for matched or
repeated measures, chi-square is for categorical data, and ANOVA is for three or more groups.
CPH Certified in Public Health Exam – Comprehensive Practice (2026/2027 Edition) Page 3
