In many instances the analysis of a dataset commences with summarizing the data, producing basic statistical measures, and then examining key properties such as the mean and variance of measured variables in more detail. The tests described in the previous sections focus on means and proportions, whereas for many investigations the variance of single and multiple datasets is equally if not more important. In this topic we describe some of the basic measures, whilst in the separate ANOVA/ANCOVA topic we cover more complex, designed frameworks that rely on analysis of variance as their core analysis approach.