Research Methods Flashcards

A researcher wants to determine whether a new vocational training program causes better employment outcomes compared to no training. Which research design best supports a causal inference?

Answer: Randomized controlled trial

A randomized controlled trial uses random assignment to control for confounds, making causal inference possible.

In a study measuring depression before and after a counseling intervention using the same instrument, which type of validity is most threatened by participants recalling their previous answers?

Answer: Internal validity due to testing effects

Testing effects (a threat to internal validity) occur when prior exposure to a measure influences later scores.

Which sampling method divides the population into subgroups and then randomly selects participants from each subgroup proportionally?

Answer: Stratified random sampling

Stratified random sampling ensures proportional representation by randomly sampling within defined subgroups.

A Likert-scale instrument produces which level of measurement?

Answer: Ordinal

Likert scales produce ordinal data because the distances between response options are not guaranteed to be equal.

When a researcher selects participants because they are easily accessible rather than through a probability method, this is called:

Answer: Convenience sampling

Convenience sampling selects participants based on availability, limiting generalizability.

A Type II error in hypothesis testing occurs when a researcher:

Answer: Fails to reject a false null hypothesis

A Type II (beta) error is failing to detect a real effect—accepting a false null hypothesis.

Which statistic describes the proportion of variance in the dependent variable explained by the independent variable?

Answer: Coefficient of determination (r²)

r² (coefficient of determination) expresses the proportion of variance in Y accounted for by X.