PSYCH291 Lecture Notes - Lecture 10: Bacon, Internal Validity, Caffeine
Document Summary
One or more independent variable is manipulated. One or more dependent variable is measured. An experimental design is able to rule out confounds and establish internal validity. A design confound occurs when another variable (aside from the iv) systematically varies between conditions. Have 1 group eat cereal before an exam, have the other eat bacon and eggs. Possible confounds: whether they had caffeine with the breakfast, how much they slept, if they re ill. Between-subjects also called independent-groups design, has different participants for each condition. Within-subjects design, also called within-groups design, has the same people testing each condition. Design confounds: other variables systematically differ between conditions. Selection effects: systematic differences in participants between conditions. Has a test of the dependent variable before and after the manipulation of the independent variable. E. g. for a test of verbal gre, test it before and after having participants get mindfulness or nutrition training. Systematic differences in participants between conditions of a between-subjects design.
