Chapter 1 Variables and Their Measurement

Naturally, we start with preliminaries. Before you learn the tools of any trade, you need to learn about your subject matter, i.e., on what you will be applying those tools. In this chapter I introduce you to the “building blocks” of statistics: the concept of variables and some related vocabulary. You will learn what variables are and about their levels of measurement (what nominal, ordinal, interval, and ratio scales are); how to determine the level of measurement of an actual existing variable and whether you should treat variables as discrete or as continuous for the purposes of statistical analysis.

Think of this chapter as the one establishing the main characters of a fictional story — the characters might seem too many at first, appearing too fast one after the other, so initially it might be hard to keep track of them and who is who and who does what. In time, however, the more you read about them (and sometimes going back to re-read key passages) they become familiar to you; then and only then you can comfortably follow their story.