CMN 548 TEST 4| ACTUAL EXAM QUESTIONS AND
CORRECT ANSWERS WITH RATIONALES
GRADED A+ LATEST: 2026/2027
CMN 548 — Test 4
1
A public health team wants to evaluate whether a new anti-smoking PSA
reduces intentions to smoke among adolescents. They randomly assign schools
to either show the PSA (treatment) or not (control) and measure intentions
before and after. Which design best describes this study?
A. Cross-sectional survey
B. Pretest-posttest randomized control trial (cluster randomized)
C. Interrupted time series
D. Quasi-experimental nonequivalent groups
Answer: B
Rationale: Schools were randomly assigned to treatment or control
(randomization at the cluster level), and intentions are measured before and
after — this is a pretest-posttest randomized control trial with clustering. It’s
not cross-sectional (which measures one time), not interrupted time series
(requires multiple time points), and not quasi-experimental since random
assignment was used.
2
Researchers conducting a content analysis code newspapers for the
presence of frames (e.g., economic, moral, legal). They calculate
,Krippendorff’s alpha for inter-coder reliability and obtain 0.55. What is the
best interpretation? A. Excellent reliability — proceed without changes.
B. Acceptable reliability for exploratory research.
C. Poor reliability — revise the codebook and retrain coders.
D. Reliability is irrelevant for content analysis.
Answer: C
Rationale: Krippendorff’s alpha values above ~0.80 are generally
considered reliable; 0.55 is low. The appropriate action is to revise the
codebook, clarify coding rules, and retrain coders to improve reliability. It’s
not excellent or acceptable; reliability is essential.
3
Which sampling technique is most likely to produce a sample representative of
the population's age distribution if age is known for the population?
A. Simple random sampling
B. Snowball sampling
C. Stratified random sampling (by age group)
D. Convenience sampling
Answer: C
Rationale: Stratified sampling ensures representation across known
subgroups (age strata) by sampling within each stratum proportionally.
Simple random sampling can by chance under/over-represent age groups;
snowball and convenience are non-probability and not representative.
4
,A study finds a statistically significant correlation of r = 0.32 (p < .01)
between social media use and depressive symptoms. Which statement is
correct? A. Social media use causes depression.
B. The correlation indicates a strong relationship.
C. The correlation indicates a moderate relationship; causality cannot be
inferred.
D. The correlation is negligible and unimportant.
Answer: C
Rationale: An r of 0.32 is a small-to-moderate effect size. Correlation does not
imply causation — without experimental or longitudinal evidence, we can't
claim causality.
5
A health campaign uses the Extended Parallel Process Model (EPPM) to design
messages. Which combination of message elements is predicted to produce
danger control (adaptive action) rather than fear control (defensive avoidance)?
A. High perceived threat, low perceived efficacy
B. Low perceived threat, high perceived efficacy
C. High perceived threat, high perceived efficacy
D. Low perceived threat, low perceived efficacy
Answer: C
Rationale: EPPM predicts danger control when both perceived threat (severity
+ susceptibility) and perceived efficacy (self + response efficacy) are high. High
threat with low efficacy leads to fear control.
, 6 (Scenario)
A nonprofit runs A/B tests on two versions of a donation landing page. Version
A shows faces of beneficiaries; Version B shows statistics about impact. Over
one week, Version A converts 3.1% (310/10,000) and Version B converts 2.6%
(260/10,000). Which statistical test is most appropriate to compare conversion
rates and why?
A. Independent-samples t-test — because you compare two means.
B. Chi-square test of independence — because you compare categorical
outcomes between groups.
C. Paired t-test — because observations are paired.
D. ANOVA — because it handles proportions.
Answer: B
Rationale: Conversion (converted / not converted) is categorical. Comparing
proportions across two independent groups is appropriately tested with a
chisquare test (or a two-proportion z-test). t-tests compare continuous means;
paired ttest requires paired data; ANOVA is for comparing means across 3+
groups.
7
In qualitative interviews, a researcher intentionally seeks participants
who represent extreme perspectives to understand rare experiences.
What is this sampling strategy called?
A. Purposive sampling — maximum variation/extreme case sampling
B. Quota sampling
C. Snowball sampling
D. Convenience sampling
CORRECT ANSWERS WITH RATIONALES
GRADED A+ LATEST: 2026/2027
CMN 548 — Test 4
1
A public health team wants to evaluate whether a new anti-smoking PSA
reduces intentions to smoke among adolescents. They randomly assign schools
to either show the PSA (treatment) or not (control) and measure intentions
before and after. Which design best describes this study?
A. Cross-sectional survey
B. Pretest-posttest randomized control trial (cluster randomized)
C. Interrupted time series
D. Quasi-experimental nonequivalent groups
Answer: B
Rationale: Schools were randomly assigned to treatment or control
(randomization at the cluster level), and intentions are measured before and
after — this is a pretest-posttest randomized control trial with clustering. It’s
not cross-sectional (which measures one time), not interrupted time series
(requires multiple time points), and not quasi-experimental since random
assignment was used.
2
Researchers conducting a content analysis code newspapers for the
presence of frames (e.g., economic, moral, legal). They calculate
,Krippendorff’s alpha for inter-coder reliability and obtain 0.55. What is the
best interpretation? A. Excellent reliability — proceed without changes.
B. Acceptable reliability for exploratory research.
C. Poor reliability — revise the codebook and retrain coders.
D. Reliability is irrelevant for content analysis.
Answer: C
Rationale: Krippendorff’s alpha values above ~0.80 are generally
considered reliable; 0.55 is low. The appropriate action is to revise the
codebook, clarify coding rules, and retrain coders to improve reliability. It’s
not excellent or acceptable; reliability is essential.
3
Which sampling technique is most likely to produce a sample representative of
the population's age distribution if age is known for the population?
A. Simple random sampling
B. Snowball sampling
C. Stratified random sampling (by age group)
D. Convenience sampling
Answer: C
Rationale: Stratified sampling ensures representation across known
subgroups (age strata) by sampling within each stratum proportionally.
Simple random sampling can by chance under/over-represent age groups;
snowball and convenience are non-probability and not representative.
4
,A study finds a statistically significant correlation of r = 0.32 (p < .01)
between social media use and depressive symptoms. Which statement is
correct? A. Social media use causes depression.
B. The correlation indicates a strong relationship.
C. The correlation indicates a moderate relationship; causality cannot be
inferred.
D. The correlation is negligible and unimportant.
Answer: C
Rationale: An r of 0.32 is a small-to-moderate effect size. Correlation does not
imply causation — without experimental or longitudinal evidence, we can't
claim causality.
5
A health campaign uses the Extended Parallel Process Model (EPPM) to design
messages. Which combination of message elements is predicted to produce
danger control (adaptive action) rather than fear control (defensive avoidance)?
A. High perceived threat, low perceived efficacy
B. Low perceived threat, high perceived efficacy
C. High perceived threat, high perceived efficacy
D. Low perceived threat, low perceived efficacy
Answer: C
Rationale: EPPM predicts danger control when both perceived threat (severity
+ susceptibility) and perceived efficacy (self + response efficacy) are high. High
threat with low efficacy leads to fear control.
, 6 (Scenario)
A nonprofit runs A/B tests on two versions of a donation landing page. Version
A shows faces of beneficiaries; Version B shows statistics about impact. Over
one week, Version A converts 3.1% (310/10,000) and Version B converts 2.6%
(260/10,000). Which statistical test is most appropriate to compare conversion
rates and why?
A. Independent-samples t-test — because you compare two means.
B. Chi-square test of independence — because you compare categorical
outcomes between groups.
C. Paired t-test — because observations are paired.
D. ANOVA — because it handles proportions.
Answer: B
Rationale: Conversion (converted / not converted) is categorical. Comparing
proportions across two independent groups is appropriately tested with a
chisquare test (or a two-proportion z-test). t-tests compare continuous means;
paired ttest requires paired data; ANOVA is for comparing means across 3+
groups.
7
In qualitative interviews, a researcher intentionally seeks participants
who represent extreme perspectives to understand rare experiences.
What is this sampling strategy called?
A. Purposive sampling — maximum variation/extreme case sampling
B. Quota sampling
C. Snowball sampling
D. Convenience sampling
