Psychological Statistics

Part I of the Study Guide for Explaining Psychological Statistics, Third Edition by Barry H. Cohen Chapter 1 Introduction to Psychological Statistics Measurement Scales Nominal B Observations are assigned to categories that differ qualitatively, but have no quantitative order (e.g., depressed, phobic, obsessive, etc.). Ordinal B The values have an order that can be represented by numbers, but the numbers cannot be used mathematically, because the intervals may not be equal (e.g., assigning ranks according to the ability of gymnasts on a team). Interval B One unit on this scale is the same size anywhere along the scale, so values can be treated mathematically (e.g., averaged), but zero on the scale does