Psychology Research Methods and Validity: Key Concepts and Designs

What are association claims?

Claims that show a relationship between variables

What are causal claims?

Claims that show one variable causes another, such as 'Getting more sleep improves grades.'

What is covariance in the context of causal claims?

Covariance means that the variables are related.

What does temporal precedence refer to?

It means the cause comes before the effect.

What is internal validity?

It ensures there are no alternative explanations for the observed effect.

What is a one-group pretest-posttest design?

A design where a single group is measured before and after a treatment without a control group.

What are the threats to internal validity in a one-group pretest-posttest design?

History, maturation, and testing effects.

What is a within-groups design?

A design where the same participants are used in all conditions.

What is a between-groups design?

A design where different participants are used in each condition.

What is a posttest-only design?

A design that measures the dependent variable only after treatment.

What is a pretest-posttest design?

A design that measures the dependent variable before and after treatment.

What is counterbalancing?

A method to vary the order of conditions to avoid order effects.

What are manipulation checks?

Tests to ensure the independent variable actually had an effect.

What is a floor effect?

When a measurement tool is too difficult, resulting in many participants scoring near the lowest possible score.

What is a ceiling effect?

When a measurement tool is too easy, causing many participants to score at or near the highest possible score.

What are selection effects?

Systematic differences between participants in different groups at the start of a study.

What is the difference between experiments and quasi-experiments?

Experiments use random assignment, while quasi-experiments do not.

What is a nonequivalent control group design?

A design that compares at least one treatment group and one comparison group without random assignment.

What is an interrupted time series design?

A design that measures a single group repeatedly before and after a treatment.

What is a nonequivalent groups interrupted time series design?

A design that involves two or more nonequivalent groups measured repeatedly before and after an intervention.

What is a stable-baseline design?

A design that takes multiple baseline measurements to ensure behavior is stable before treatment.

What is a reversal (ABAB) design?

A design where interventions are introduced at different times across different behaviors or individuals.

What is a multiple-baseline design?

A design that applies a treatment at different times across subjects or behaviors to demonstrate causation.

What are the four big validities?

Construct validity, internal validity, external validity, and statistical validity.

What is the null hypothesis (H₀)?

The hypothesis stating there is no effect.

What is the alternative hypothesis (H₁)?

The hypothesis stating there is an effect.

What are the four steps involved in hypothesis testing?

1. State hypotheses, 2. Set decision rule, 3. Calculate test statistic, 4. Make decision.

What is the purpose of using critical value charts in hypothesis testing?

To determine the decision rule based on alpha and degrees of freedom.

How do you calculate an r-value?

By using the correlation formula for a small data set.

How do you calculate a t-value?

By using the t-test formula for a small data set.