• exploratory analysis

One of the more important but often overlooked parts of statistical analysis is the very first step—an exploratory and descriptive analysis. Typically, researchers take a quick look at the data and then dive into more complex regression models or t tests. In this column, I discuss preliminary analysis in general and look at some techniques less well known than others, but which provide interesting and useful results.

The first step in understanding your data is to establish the kinds of variables you have. Are they continuous (ranging over several values, like weight or height) or categorical (taking only a few values)? Are the continuous variables bounded (like age, which can't be less than zero) or unbounded? …