3001-3 Flashcards
Experimental Design
Independent groups design (between subjects Design)
Repeated measures design (within-subjects design)
Independent groups design (between subjects Design)
an experimental design where different participants are assigned to separate groups, with each group experiencing only one level of the independent variable.
Repeated measures design (within-subjects design)
an experimental design where the same participants are exposed to all levels of the independent variable, allowing comparisons within the same group.
Types of Independent Group Designs
Posttest-only design
Pretest-posttest design
Solomon four-group design
Posttest-only design
An experimental design where participants are randomly assigned to different groups and are measured on the dependent variable only after the treatment or intervention has occurred, without any pretest.
Pretest-posttest design
an experimental design where participants are measured on the dependent variable before (pretest) and after (posttest) the treatment or intervention, allowing comparisons of changes over time.
Solomon four-group design
an experiment with four groups: two get a pretest and a posttest, and two only get a posttest. This design helps to check if the pretest influences the results.
Contrast effects (interference effects)
happen when participants’ responses are influenced by previous experiences or conditions, making them compare or judge the current situation differently than they would have otherwise.
complete counterbalancing
a technique used in experiments where all possible orders of the conditions are presented to participants, ensuring that each condition appears in every possible sequence to control for order effects.
incomplete counterbalancing
a technique where only a subset of all possible orders of conditions is used in an experiment, typically to reduce the number of participants needed, while still controlling for order effects.
order effects
occur when the sequence in which participants experience different conditions in an experiment influences their responses, potentially skewing the results. Examples include practice effects or fatigue effects.
Matched Pairs Design
An experimental design where participants are paired based on similar characteristics (e.g., age, ability) and then randomly assigned to different experimental conditions.
non-directional (two-tailed) test
when the alternative hypothesis merely predicts a difference between groups (e.g., “The means of Group 1 and Group
2 will be different.”)
directional (one-tailed) test
when the alternative hypothesis predicts a difference between groups AND the direction of the difference
confound
An external factor that messes with the results of an experiment, making it hard to know if the effect is caused by the independent variable or something else.
Independent-groups t-test
Subjects in the groups are independent of each other
Related-samples/Repeated-measures t-test
Same subjects in all conditions or related pairs of subjects in the groups
One-way independent-groups ANOVA
or more levels of one IV (3 or more experimental conditions)
- Subjects in the groups are independent of each other
One-way repeated-measures ANOVA
3 or more levels of one IV (3 or more experimental conditions)
- Same subjects perform in all conditions
Comparing the means of 2 samples:
(1) Independent-groups t-test
(2) Related-samples/Repeated-measures t-test
Comparing the means of 3 or more samples
(1) One-way independent-groups ANOVA
(2) One-way repeated-measures ANOVA
