APPLIED MULTIVARIATE STATISTICS: WITH SAS® SOFTWARE

6.6. Analysis in the Presence of Covariates

In many biological, medical and industrial applications, we often come across repeated measures data along with covariates that influence the response variable. It is important to account for the effects of such covariates. In clinical trials, the baseline measurements can be thought of as the useful covariates for analyzing response patterns at successive visits. For example, in therapies for the treatment of chronic stable angina, treadmill walking time (a covariate) is recorded just before the administration of a dose, and then at some post-dose times. The effectiveness of the visit doses is evaluated relative to the corresponding baseline walking times (Patel, 1986). Here the covariate information ...