NPE Research Methods and Statistics 1 — Questions and Answers
Question 1: Which research design allows investigators to draw causal conclusions about the relationship between variables?
- Correlational study
- Case study
- True experimental design (Correct answer)
- Naturalistic observation
Correct answer: True experimental design
True experimental designs with random assignment and manipulation of an independent variable are the only designs that support causal inferences.
Question 2: A researcher finds a p-value of 0.03 using an alpha level of 0.05. What is the correct interpretation?
- The null hypothesis is proven true
- The result is statistically significant and the null hypothesis is rejected (Correct answer)
- The effect size is large
- The probability of replication is 97%
Correct answer: The result is statistically significant and the null hypothesis is rejected
A p-value of 0.03 is below the alpha level of 0.05, so the null hypothesis is rejected and the result is considered statistically significant.
Question 3: Which type of validity refers to the degree to which a test actually measures the construct it purports to measure?
- Predictive validity
- Face validity
- Construct validity (Correct answer)
- Content validity
Correct answer: Construct validity
Construct validity evaluates whether a test truly captures the theoretical construct it is designed to measure.
Question 4: In a double-blind randomized controlled trial, which parties are unaware of the treatment condition assignment?
- Only the participants
- Only the researchers
- Both participants and researchers administering the treatment (Correct answer)
- The IRB and institutional review committee
Correct answer: Both participants and researchers administering the treatment
In a double-blind design, both participants and the researchers interacting with them are unaware of group assignment, reducing expectancy and placebo effects.
Question 5: A psychologist administers the same test twice to a group of clients one month apart. She is assessing which type of reliability?
- Inter-rater reliability
- Internal consistency
- Test-retest reliability (Correct answer)
- Parallel forms reliability
Correct answer: Test-retest reliability
Test-retest reliability measures the stability of scores over time by correlating results from two administrations of the same test.
Question 6: Which statistical test is most appropriate for comparing the means of two independent groups on a continuous outcome variable?
- Chi-square test
- Independent samples t-test (Correct answer)
- Pearson correlation
- Mann-Whitney U test
Correct answer: Independent samples t-test
The independent samples t-test is designed to compare means of two separate groups on a continuous, normally distributed variable.
Question 7: What is the primary purpose of random assignment in experimental research?
- To increase the sample size
- To ensure generalizability to the population
- To equate groups on known and unknown confounding variables (Correct answer)
- To reduce measurement error in self-report scales
Correct answer: To equate groups on known and unknown confounding variables
Random assignment distributes both known and unknown confounds evenly across groups, enabling causal attribution to the independent variable.
NPE Research Methods and Statistics 1
Which research design allows investigators to draw causal conclusions about the relationship between variables?