In this article, the authors talk about variation and how variation between measurements may be reduced if sampling is not random. They also talk about replication and its variants. A replicate is a repeated measurement from the same experimental unit. An experimental unit is the smallest part of an experiment or a study that can be subject to a…

In this article, the authors consider the possibility that groups could be different, because of the different conditions of a factor. This is as far as the analysis can extend: the consideration is restricted to groups characterized by the different category of the factor being considered. In many biological experiments, the factor considered may…

How effective is training frogs to jump? This is perhaps the most frequent question in biology that is subjected to statistical analysis: does a treatment make a difference? One can examine whether there is indeed a training effect, by first assuming the opposite. That is, the authors assume that training has no effect on the mean distance jumped.…