CALIFORNIA STATISTICS FOR
PSYCHOLOGY EXAM WITH QUESTIONS AND
VERIFIED ANSWERS, PLUS DETAILED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A psychology researcher measures the reaction times of 200
participants after exposure to a visual stimulus. The reaction times
are recorded in milliseconds. Which level of measurement best
describes reaction time?
A. Nominal
B. Ordinal
C. Interval
D. Ratio
Answer: D. Ratio
Rationale: Reaction time has equal intervals between values and a
meaningful absolute zero. A reaction time of 0 milliseconds represents
an absence of elapsed reaction time, making ratio-level measurement
appropriate. Ratio data permit all arithmetic operations, including
meaningful comparisons such as “twice as long.”***
2. A psychologist categorizes participants according to their primary
diagnosis: anxiety disorder, depressive disorder, bipolar disorder,
or schizophrenia-spectrum disorder. What type of measurement
scale is being used?
A. Ratio
B. Interval
1
,C. Ordinal
D. Nominal
Answer: D. Nominal
Rationale: Diagnostic categories are labels rather than numerical
quantities with meaningful order. Nominal variables classify
observations into mutually exclusive categories. Although some
diagnoses might be perceived as more or less severe, the categories
themselves do not inherently establish a statistical ranking.***
3. A researcher obtains the following anxiety scores: 4, 6, 6, 8, 11.
What is the arithmetic mean?
A. 6
B. 7
C. 7.0
D. 8
Answer: C. 7.0
Rationale: Add the observations: 4 + 6 + 6 + 8 + 11 = 35. Divide by the
five observations: 35 ÷ 5 = 7. The mean is therefore 7.0. The mean
incorporates every observation in the dataset and is particularly useful
when the distribution is reasonably symmetric.***
4. A distribution of depression scores contains the values 3, 5, 7, 8, 9,
12, and 30. Which measure of central tendency would generally be
most resistant to the extremely high score of 30?
A. Mean
B. Median
C. Variance
D. Standard deviation
2
,Answer: B. Median
Rationale: The median is the middle score when observations are
ordered. Extreme values have much less influence on the median than on
the mean. The score of 30 would substantially increase the mean but
would not change the median's position in the ordered dataset.***
5. A psychology professor reports that students' test scores have a
mean of 80 and a standard deviation of 10. Approximately what
percentage of scores would fall between 70 and 90 if the
distribution is approximately normal?
A. 34%
B. 50%
C. 68%
D. 95%
Answer: C. 68%
Rationale: In an approximately normal distribution, about 68% of
observations fall within one standard deviation of the mean. Here, 70 is
one standard deviation below the mean and 90 is one standard deviation
above it. Thus approximately 68% of scores are expected within that
range.***
6. A participant scores 90 on a psychological test with a mean of 70
and a standard deviation of 10. What is the participant's z-score?
A. −2.00
B. −1.00
C. +1.00
D. +2.00
Answer: D. +2.00
3
, Rationale: The z-score is calculated as z = (X − μ) / σ. Therefore, z =
(90 − 70) / 10 = 20/10 = +2. The participant scored two standard
deviations above the mean.***
7. A z-score of −1.50 indicates that an individual's score is:
A. 1.5 points below the mean
B. 1.5 standard deviations below the mean
C. 1.5 standard deviations above the mean
D. 150% below the mean
Answer: B. 1.5 standard deviations below the mean
Rationale: A z-score expresses a raw score's distance from the mean in
standard deviation units. A negative z-score indicates a score below the
mean, while the magnitude of 1.50 indicates the distance is 1.5 standard
deviations.***
8. Which statistic describes the average squared deviation of
observations from the mean?
A. Range
B. Variance
C. Median
D. Standard error
Answer: B. Variance
Rationale: Variance is calculated by averaging squared deviations from
the mean, with adjustments depending on whether the researcher is
calculating a population or sample variance. Squaring deviations
prevents positive and negative deviations from canceling each other.
Standard deviation is the square root of variance.***
4
PSYCHOLOGY EXAM WITH QUESTIONS AND
VERIFIED ANSWERS, PLUS DETAILED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A psychology researcher measures the reaction times of 200
participants after exposure to a visual stimulus. The reaction times
are recorded in milliseconds. Which level of measurement best
describes reaction time?
A. Nominal
B. Ordinal
C. Interval
D. Ratio
Answer: D. Ratio
Rationale: Reaction time has equal intervals between values and a
meaningful absolute zero. A reaction time of 0 milliseconds represents
an absence of elapsed reaction time, making ratio-level measurement
appropriate. Ratio data permit all arithmetic operations, including
meaningful comparisons such as “twice as long.”***
2. A psychologist categorizes participants according to their primary
diagnosis: anxiety disorder, depressive disorder, bipolar disorder,
or schizophrenia-spectrum disorder. What type of measurement
scale is being used?
A. Ratio
B. Interval
1
,C. Ordinal
D. Nominal
Answer: D. Nominal
Rationale: Diagnostic categories are labels rather than numerical
quantities with meaningful order. Nominal variables classify
observations into mutually exclusive categories. Although some
diagnoses might be perceived as more or less severe, the categories
themselves do not inherently establish a statistical ranking.***
3. A researcher obtains the following anxiety scores: 4, 6, 6, 8, 11.
What is the arithmetic mean?
A. 6
B. 7
C. 7.0
D. 8
Answer: C. 7.0
Rationale: Add the observations: 4 + 6 + 6 + 8 + 11 = 35. Divide by the
five observations: 35 ÷ 5 = 7. The mean is therefore 7.0. The mean
incorporates every observation in the dataset and is particularly useful
when the distribution is reasonably symmetric.***
4. A distribution of depression scores contains the values 3, 5, 7, 8, 9,
12, and 30. Which measure of central tendency would generally be
most resistant to the extremely high score of 30?
A. Mean
B. Median
C. Variance
D. Standard deviation
2
,Answer: B. Median
Rationale: The median is the middle score when observations are
ordered. Extreme values have much less influence on the median than on
the mean. The score of 30 would substantially increase the mean but
would not change the median's position in the ordered dataset.***
5. A psychology professor reports that students' test scores have a
mean of 80 and a standard deviation of 10. Approximately what
percentage of scores would fall between 70 and 90 if the
distribution is approximately normal?
A. 34%
B. 50%
C. 68%
D. 95%
Answer: C. 68%
Rationale: In an approximately normal distribution, about 68% of
observations fall within one standard deviation of the mean. Here, 70 is
one standard deviation below the mean and 90 is one standard deviation
above it. Thus approximately 68% of scores are expected within that
range.***
6. A participant scores 90 on a psychological test with a mean of 70
and a standard deviation of 10. What is the participant's z-score?
A. −2.00
B. −1.00
C. +1.00
D. +2.00
Answer: D. +2.00
3
, Rationale: The z-score is calculated as z = (X − μ) / σ. Therefore, z =
(90 − 70) / 10 = 20/10 = +2. The participant scored two standard
deviations above the mean.***
7. A z-score of −1.50 indicates that an individual's score is:
A. 1.5 points below the mean
B. 1.5 standard deviations below the mean
C. 1.5 standard deviations above the mean
D. 150% below the mean
Answer: B. 1.5 standard deviations below the mean
Rationale: A z-score expresses a raw score's distance from the mean in
standard deviation units. A negative z-score indicates a score below the
mean, while the magnitude of 1.50 indicates the distance is 1.5 standard
deviations.***
8. Which statistic describes the average squared deviation of
observations from the mean?
A. Range
B. Variance
C. Median
D. Standard error
Answer: B. Variance
Rationale: Variance is calculated by averaging squared deviations from
the mean, with adjustments depending on whether the researcher is
calculating a population or sample variance. Squaring deviations
prevents positive and negative deviations from canceling each other.
Standard deviation is the square root of variance.***
4
