A variable is a characteristic or condition that can change or take on different values.
Most research begins with a general question about the relationship between two variables for a specific group of individuals.
a variable whose value is obtained by counting, e.g. class size
discrete variables
are infinitely divisible into whatever units a researcher may choose, e.g. with decimals
continuous variables
To define the units for a continuous variable, a researcher must use real limits which are boundaries located exactly half-way between adjacent categories.
To establish relationships between variables, researchers must observe the variables and record their observations. This requires that the variables be measured.
The process of measuring a variable requires a set of categories called a scale of measurement and a process that classifies each individual into one category.
