Variable

- A case or observation has many traits or variables. Each case should be independent of the other, for example a person - A variable is  any trait that can change values from case to case, for example gender and income.

Levels of measurement - Variables can be measured on three levels: 1. Nominal level– Unrankable categories 2. Ordinal level – Rank or orderable categories 3. Numerical level – Numbers - Numerical variables are numbers, Ordinal variables ordain, and nominal variables name