CALIFORNIA EXPERIMENTAL PSYCHOLOGY
EXAM WITH QUESTIONS AND VERIFIED
ANSWERS, PLUS DETAILED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A researcher wants to determine whether sleep deprivation causes
impaired working-memory performance. Participants are randomly
assigned to either 4 hours or 8 hours of sleep before completing a
standardized memory task. Which feature most directly allows the
researcher to make a causal inference?
A. Use of a standardized memory test
B. Random assignment to sleep conditions
C. Large sample size
D. Correlation between sleep duration and memory scores
Answer: B. Random assignment to sleep conditions
Rationale: Random assignment distributes participant characteristics
across experimental conditions on average, reducing systematic
preexisting differences between groups. Because the researcher
manipulates sleep duration and randomly assigns participants,
differences in memory performance can more confidently be attributed
to the experimental manipulation rather than preexisting group
differences.
2. In an experiment examining whether background noise affects
concentration, participants complete the same attention task under
quiet, moderate-noise, and high-noise conditions. If every
1
,participant experiences all three conditions, which design is being
used?
A. Independent-groups design
B. Between-subjects factorial design
C. Within-subjects design
D. Matched-groups design
Answer: C. Within-subjects design
Rationale: A within-subjects design exposes the same participants to
every experimental condition. Each participant therefore serves as
their own control, which can substantially reduce error caused by
individual differences. However, researchers must consider order
effects and may use counterbalancing to address them.
3. A psychologist finds that participants who spend more hours
studying tend to obtain higher examination scores. The correlation
is r = +0.72. What is the most appropriate interpretation?
A. Studying causes higher examination scores in 72% of participants
B. There is a strong positive association between studying and
examination scores
C. Examination scores cause students to study more
D. The variables have no meaningful relationship
Answer: B. There is a strong positive association between studying
and examination scores
Rationale: A positive correlation indicates that higher values of one
variable tend to be associated with higher values of the other. The
magnitude of .72 indicates a relatively strong linear association.
However, correlation alone does not establish causation because third
variables and reverse causation remain possible.
2
,4. A researcher operationalizes “test anxiety” as a participant's
score on a 20-item validated anxiety questionnaire administered
immediately before an examination. What does the operational
definition accomplish?
A. It eliminates measurement error
B. It defines exactly how the construct will be measured
C. It proves the construct causes examination performance
D. It establishes external validity
Answer: B. It defines exactly how the construct will be measured
Rationale: An operational definition translates an abstract
psychological construct into a measurable procedure. “Test anxiety” is
theoretical, whereas a specified questionnaire score provides an
observable measurement. Operationalization is essential for
replication and empirical testing.
5. A study reports p = .03 for the difference between two
experimental groups. Assuming α = .05, which conclusion is most
appropriate?
A. The null hypothesis must be true
B. The result is statistically significant at the .05 level
C. There is a 3% probability that the experimental hypothesis is true
D. The result proves the effect is practically important
Answer: B. The result is statistically significant at the .05 level
Rationale: Because p = .03 is below the predetermined significance
level of .05, the researcher rejects the null hypothesis under the
conventional decision rule. Statistical significance does not establish
the probability that the hypothesis is true and does not necessarily
indicate that the effect is practically meaningful.
3
, 6. Which situation represents a Type I error?
A. Failing to detect a real effect
B. Concluding that an effect exists when it actually does not
C. Obtaining a statistically significant result from a true alternative
hypothesis
D. Increasing statistical power
Answer: B. Concluding that an effect exists when it actually does not
Rationale: A Type I error occurs when the researcher rejects a true
null hypothesis. It is commonly described as a false positive. The
probability of a Type I error is controlled by the selected alpha level,
such as .05.
7. Which situation represents a Type II error?
A. Rejecting a true null hypothesis
B. Accepting an alternative hypothesis that is false
C. Failing to detect a genuine effect
D. Obtaining an unusually large effect size
Answer: C. Failing to detect a genuine effect
Rationale: A Type II error occurs when a researcher fails to reject the
null hypothesis even though a real effect exists. Statistical power is the
probability of detecting an effect when that effect truly exists, so
increasing power generally decreases the likelihood of a Type II error.
8. A researcher increases sample size while holding the effect size
and significance criterion constant. What will generally happen?
A. Statistical power decreases
B. Standard error increases
4
EXAM WITH QUESTIONS AND VERIFIED
ANSWERS, PLUS DETAILED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A researcher wants to determine whether sleep deprivation causes
impaired working-memory performance. Participants are randomly
assigned to either 4 hours or 8 hours of sleep before completing a
standardized memory task. Which feature most directly allows the
researcher to make a causal inference?
A. Use of a standardized memory test
B. Random assignment to sleep conditions
C. Large sample size
D. Correlation between sleep duration and memory scores
Answer: B. Random assignment to sleep conditions
Rationale: Random assignment distributes participant characteristics
across experimental conditions on average, reducing systematic
preexisting differences between groups. Because the researcher
manipulates sleep duration and randomly assigns participants,
differences in memory performance can more confidently be attributed
to the experimental manipulation rather than preexisting group
differences.
2. In an experiment examining whether background noise affects
concentration, participants complete the same attention task under
quiet, moderate-noise, and high-noise conditions. If every
1
,participant experiences all three conditions, which design is being
used?
A. Independent-groups design
B. Between-subjects factorial design
C. Within-subjects design
D. Matched-groups design
Answer: C. Within-subjects design
Rationale: A within-subjects design exposes the same participants to
every experimental condition. Each participant therefore serves as
their own control, which can substantially reduce error caused by
individual differences. However, researchers must consider order
effects and may use counterbalancing to address them.
3. A psychologist finds that participants who spend more hours
studying tend to obtain higher examination scores. The correlation
is r = +0.72. What is the most appropriate interpretation?
A. Studying causes higher examination scores in 72% of participants
B. There is a strong positive association between studying and
examination scores
C. Examination scores cause students to study more
D. The variables have no meaningful relationship
Answer: B. There is a strong positive association between studying
and examination scores
Rationale: A positive correlation indicates that higher values of one
variable tend to be associated with higher values of the other. The
magnitude of .72 indicates a relatively strong linear association.
However, correlation alone does not establish causation because third
variables and reverse causation remain possible.
2
,4. A researcher operationalizes “test anxiety” as a participant's
score on a 20-item validated anxiety questionnaire administered
immediately before an examination. What does the operational
definition accomplish?
A. It eliminates measurement error
B. It defines exactly how the construct will be measured
C. It proves the construct causes examination performance
D. It establishes external validity
Answer: B. It defines exactly how the construct will be measured
Rationale: An operational definition translates an abstract
psychological construct into a measurable procedure. “Test anxiety” is
theoretical, whereas a specified questionnaire score provides an
observable measurement. Operationalization is essential for
replication and empirical testing.
5. A study reports p = .03 for the difference between two
experimental groups. Assuming α = .05, which conclusion is most
appropriate?
A. The null hypothesis must be true
B. The result is statistically significant at the .05 level
C. There is a 3% probability that the experimental hypothesis is true
D. The result proves the effect is practically important
Answer: B. The result is statistically significant at the .05 level
Rationale: Because p = .03 is below the predetermined significance
level of .05, the researcher rejects the null hypothesis under the
conventional decision rule. Statistical significance does not establish
the probability that the hypothesis is true and does not necessarily
indicate that the effect is practically meaningful.
3
, 6. Which situation represents a Type I error?
A. Failing to detect a real effect
B. Concluding that an effect exists when it actually does not
C. Obtaining a statistically significant result from a true alternative
hypothesis
D. Increasing statistical power
Answer: B. Concluding that an effect exists when it actually does not
Rationale: A Type I error occurs when the researcher rejects a true
null hypothesis. It is commonly described as a false positive. The
probability of a Type I error is controlled by the selected alpha level,
such as .05.
7. Which situation represents a Type II error?
A. Rejecting a true null hypothesis
B. Accepting an alternative hypothesis that is false
C. Failing to detect a genuine effect
D. Obtaining an unusually large effect size
Answer: C. Failing to detect a genuine effect
Rationale: A Type II error occurs when a researcher fails to reject the
null hypothesis even though a real effect exists. Statistical power is the
probability of detecting an effect when that effect truly exists, so
increasing power generally decreases the likelihood of a Type II error.
8. A researcher increases sample size while holding the effect size
and significance criterion constant. What will generally happen?
A. Statistical power decreases
B. Standard error increases
4
