Paired Replicates Data

Paired replicates is the simplest form of repeated measures data, when only two measurements are made for each experimental unit.

Consider, for example, a study of 2 drugs – A and B – to determine whether they reduce arterial blood pressure. There are 10 patients, and each patient takes both drugs, but at widely separated times. The outcome of such a study for 10 patients (experimental units) can be represented in the following table as the magnitude of blood pressure decline 3 hours after the drug intake:

Statistical methods for the analysis of repeated measures data are applicable to paired replicates too, as to a special case. On the other hand, there are also methods applicable only to paired replicates data, for example the sign test, the Wilcoxon signed ranks test.