PC PC Data Analysis and Interpretation 1 — Questions and Answers
Question 1: Which statistical measure is used to describe the spread of scores around the mean in a psychometric dataset?
- Standard deviation (Correct answer)
- Median
- Mode
- Range only
Correct answer: Standard deviation
Standard deviation quantifies how much individual scores deviate from the mean, making it the primary measure of score spread.
Question 2: In psychometric data analysis, a correlation coefficient of 0.00 indicates:
- A perfect positive relationship
- No linear relationship between variables (Correct answer)
- A perfect negative relationship
- Moderate positive correlation
Correct answer: No linear relationship between variables
A correlation coefficient of 0.00 indicates no linear relationship exists between the two variables being studied.
Question 3: When interpreting a percentile rank of 75 on a psychometric test, a psychometrician would conclude that the examinee:
- Answered 75% of items correctly
- Scored higher than 75% of the norm group (Correct answer)
- Is in the top 25% of all possible scores
- Has a scaled score of 75
Correct answer: Scored higher than 75% of the norm group
A percentile rank of 75 means the examinee scored equal to or higher than 75% of individuals in the normative reference group.
Question 4: Which type of score transformation converts raw scores to a distribution with a mean of 50 and standard deviation of 10?
- Z-scores
- T-scores (Correct answer)
- Stanines
- NCE scores
Correct answer: T-scores
T-scores are standardized scores with a fixed mean of 50 and standard deviation of 10, commonly used in psychological assessments.
Question 5: Factor analysis in psychometrics is primarily used to:
- Establish test-retest reliability
- Identify underlying constructs that explain item correlations (Correct answer)
- Calculate standard error of measurement
- Determine sample size requirements
Correct answer: Identify underlying constructs that explain item correlations
Factor analysis identifies latent constructs or dimensions that account for the pattern of correlations among test items.
Question 6: A psychometrician analyzing item difficulty would flag an item with a p-value of 0.95 because it:
- Is too difficult for the population
- Is too easy and provides little discrimination (Correct answer)
- Has poor construct validity
- Shows negative point-biserial correlation
Correct answer: Is too easy and provides little discrimination
A p-value of 0.95 means 95% of examinees answered correctly, indicating the item is too easy to effectively differentiate ability levels.
PC PC Data Analysis and Interpretation 1
Which statistical measure is used to describe the spread of scores around the mean in a psychometric dataset?