Types of Data › Introduction

Data type influences your choice of statistical methods, visualization techniques, and machine learning algorithms. Classifying variables carefully helps you choose suitable techniques and interpret their results, but it does not replace checks of data quality, design, and modeling assumptions.

In this chapter, we'll use a common introductory hierarchy. It separates quantitative from qualitative data, then distinguishes discrete from continuous quantitative data and nominal from ordinal qualitative data. Terminology varies across fields, so the meaning of a variable is more important than the label alone.