KL Ch. 21 Randomized group and correlated groups Flashcards
Factorial Design
the structure of research in which two or more independent variables are juxtaposed in order to study their independent and interactive effects on a dependent variable. The simplest factorial design is 2x2, but designs can have more than 2 variables (3x2x2)
Randomized subject designs
control for history and maturation because so little time elapses between manipulation (x) and observation (y)
Correlated Groups
There is a systematic variance in the dependent variable measures due to the correlation between the groups on some variable related to the dependent variable. This design capitalizes on differences between units
Correlated Groups correlations
o use the same units (ex: participants)
o match units on one or more independent variables related to the dependent variable.
o use more than one group of units (ex: classes, schools)
One Group, Repeated Trials
Pretest sensitization and maturation are problems with this design. In an analysis of ‘time’, this is the implicit design
• Two groups, experimental group-control group designs
participants matched, then assigned to experimental and control groups at random
Factorial Correlated Groups
factorial design with units notion
Analysis of Covariance
form of analysis that tests significance of differences among means of experimental groups after taking into account initial differences among groups, and the correlation of initial measures and the dependent variable measures. Multiple regression can also be used for this purpose. The measure used as a control variable (pretest) is called a covariate.