8.1 Introduction

Main distinctions: Numbers as numbers vs. as ranks vs. as (categorical) labels.

Example: How tall are people?

The same measurement can be made (mapped, represented) on different scales:

  1. size in cm: comparisons between values are scaled (e.g., 20% larger, etc.)

  2. rank within group: comparisons between people are possible, but no longer scaled

  3. categories: can be ordered (small-medium-tall) or unordered (fits vs. does not fit)

Why relevant?

  • They allow different types of calculations and tests.
  • They should be assigned to different data types.