Читать книгу Planning and Executing Credible Experiments - Robert J. Moffat - Страница 28

A quantitative property can be measured. A categorical property can be recorded but not measured.

The act of measurement is an ordering in a scalar system involving a “less than, equal to, or greater than” test. We assign a value to the measurand by comparing it with a standard interval and counting the number of intervals equal to the measurand. The only attributes of any system that can be measured are those which can be put into one‐to‐one correspondence with points on the real number line. Since only the real number system has the order property, only real numbers (scalars) can be measured.