Data Classification

Data Classification

In this chapter, you'll learn the difference between quantitative and qualitative data. You'll also learn about ratio, interval, ordinal, and nominal data types, and what operations you can perform on each of them.

Quantitative and Qualitative Data

All data is either quantitative – measured with some kind of measuring implement, such as a ruler, jug, weighing scales, stopwatch, thermometer, and so on – or is qualitative: an observed feature of interest that is placed into categories, as in health (healthy, sick), and opinion (agree, neutral, disagree).

Quantitative and qualitative data can be sub-divided into four further classes of data – Ratio, Interval, Ordinal, and Nominal – as shown in Figure 2.1.

Figure 2.1: There are four distinct types of data

The differences between them can be established by asking just three questions:

Question 1: Are adjacent data points...