Variables

The thing measured is generally some trait, attribute, quality, or quantity. Because measurement of one person, or one object generally varies from those of another person or object, the thing measured is called a variable. There are characteristics that can take on different values for all member of the group under study. These variables are of two types: continuous or discrete.

When measurements of a variable are arranged in some sort of order - from large to small, good to bad, from few to many, and so forth - we have a series. A series may be "continuous", that is measurements may be found on almost every part of the scale. Measurements of height, weight, or temperature represent a continuous series. Although the scale is graded, one can find individuals at any point on the scale.