APA Research Methods and Statistics 2

Question 1

A researcher measures anxiety before and after a treatment in the same group. Which statistical test is most appropriate?

Accepted Answer

Paired-samples t-test

Answer

The paired-samples (dependent) t-test compares means from two related measurements taken from the same participants.

Question 2

What does internal validity refer to in psychological research?

Accepted Answer

The degree to which changes in the DV are caused by the IV

Answer

Internal validity concerns whether observed changes in the dependent variable are genuinely caused by manipulation of the independent variable, ruling out confounds.

Question 3

Which sampling method gives every member of the population an equal chance of being selected?

Accepted Answer

Simple random sampling

Answer

Simple random sampling uses a process (e.g., lottery or random number generator) that gives each population member an equal probability of selection.

Question 4

In APA Publication Manual format, how should a statistically non-significant result be reported?

Accepted Answer

p > .05 with actual p-value, e.g., p = .21

Answer

APA recommends reporting the exact p-value regardless of significance (e.g., p = .21) rather than only noting p > .05 or 'NS'.

Question 5

What is the main advantage of a within-subjects design over a between-subjects design?

Accepted Answer

It requires fewer participants and reduces error variance

Answer

Within-subjects designs use each participant as their own control, reducing individual-difference error and requiring fewer total participants.

APA - American Psychological Association Practice Test

APA - American Psychological Association Practice Test

APA Research Methods and Statistics 2