Clinical Trials

Clinical Trials: A Practical Guide ■❚❙❘Figure 1. Response profiles for 20 participants from Dataset I.220Systolic blood pressure (mm Hg)2001801601401 2 3 4Visitrepeated measures is exchangeable with between- and within-subject standarddeviations both equal to 10 units. Formally, this model can be written:R ij= 150 + 10V 2j+ 20V 3j+ 30V 4j+ 10T i+ u i+ ε ijwith u i∼ N(0,100) and ε ij∼ N(0,100)where:• R ij= the response for the ith participant at the jth visit• V kj= 1 if j = k and 0 otherwise• T i= 1 if the ith participant is in group B and 0 if the ith participantis in group AUsing this equation, we simulated 4,000 participants to give a dataset (Dataset I).Figure 1 shows the response profile of 20 randomly selected participants.Figure 2 presents the mean responses over visit by treatment, reflecting thepatterns described in the equation.345