PS295 Lecture Notes - Lecture 15: Repeated Measures Design, Random Assignment, Demand Characteristics
Document Summary
A two group experimental design is the simplest one way design. It includes only one iv with two levels (ex two conditions) Ex memory for positive words vs memory for negative words. Most experiments include more than 2 levels of iv. Between subjects design implies groups are mutually exclusive. Three main types of one way designs: randomized groups design: Participants are randomly assigned to one of the two experimental conditions and cannot be in more than one: matched subjects design: Participants are first matched into blocks and then randomly assigned to one condition: repeated measures design: Advantages of pre-test post-test designs: pretest allows researcher to verify participants were equalized across conditions before. Iv is manipulated: pretest provides baseline data for evaluating the effect of the iv, more powerful than prettest-only designs. Variability in pretest scores can be statistically removed during analysis. Error variance due to individual differences is removed making the effects of the iv easier to detect.
