APA Research Methods and Statistics

Question 1

Which research design allows researchers to establish cause-and-effect relationships between variables?

Accepted Answer

True experiment

Answer

True experiments use random assignment and manipulation of an independent variable, which is the only design that allows causal conclusions.

Question 2

In APA-style reporting, what does a p-value of .03 indicate?

Accepted Answer

There is a 3% probability the results occurred by chance if H₀ is true

Answer

A p-value of .03 means there is a 3% probability of obtaining results at least as extreme as observed if the null hypothesis were true.

Question 3

Which measure of central tendency is most affected by extreme outliers?

Accepted Answer

Mean

Answer

The mean uses every data point in its calculation, so extreme outliers can substantially pull it in their direction.

Question 4

What is the purpose of a double-blind procedure in experimental research?

Accepted Answer

To reduce demand characteristics and experimenter bias

Answer

In a double-blind study, neither participants nor researchers who interact with them know group assignments, reducing bias from both sides.

Question 5

According to APA guidelines, which correlation coefficient magnitude is typically considered 'large'?

Accepted Answer

.70 or above

Answer

Cohen's conventions define a large correlation as r ≥ .50, with many researchers treating .70+ as clearly large.

APA - American Psychological Association Practice Test