PSYC 203 Lecture Notes - Lecture 9: Eyewitness Memory, Random Assignment, Repeated Measures Design
16 Mar 2016
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Each level of the independent variable contains a diferent group of subjects. Counter-balancing to minimize confounding efects: ex. have everyone do study condiions in the same order. Necessary when: subject variable is the independent variable (ex. sex, subjects in each condiion have to be na ve, decepion (ex. eyewitness memory study, would prefer to use within-subjects design wherever possible. Disadvantages: more subjects needed (each paricipant can only experience 1 condiion, costlier in ime and resources, diferences between the condiions could be due to the independent variable, but could also be due to diferences between the groups. Each subject needs equal chance of being placed in any group in study. Spreads potenial confounds equally through all groups: block randomizaion (3 groups: a, b, c) Order of groups in each block are randomized. Assign paricipants to blocks then get a group. Small numbers per group might cause random assignment to fail. Each paricipant is exposed to every level of the independent variable.
