PSY 4603 Research Methods. Analysis of Covariance & the Randomized Blocks Design (Designs With A Control or Concomitant Variable). Introduction Completely randomized designs share a common problem: They are relatively deficient in power.
PSY 4603 Research Methods
Analysis of Covariance
Randomized Blocks Design
(Designs With A Control or Concomitant Variable)
Correlation Between the initial grouping of subjects into blocks and then the random assignment of subjects within each block to the different conditions.
Blocking Variable & the
(1) to refine estimates of experimental error and
(2) to adjust treatment effects for any differences between the treatment groups that existed before the experimental treatments were administered.
When we look at our analysis of covariance, one of the first things we see is that MSerror (71.539) is about one-third smaller than it was in the analysis of variance. This is due to the fact that the covariate (Distractability [DS]) was able to explain much of the variability in Errors that had been left unexplained in the analysis of variance.