Definition
Data variable
A data variable is a characteristic recorded for every case in a data set.
What it means
A variable tells what question is asked about every case. In a class survey, “favourite fruit” is one variable and “height in centimetres” is another. The children are the cases; their answers are the variable’s values.
Remember it
Variable = the same question for each case; values = the answers.
Example
A pet survey records animal type and number of pets for each family. “Animal type” is a categorical data variable. “Number of pets” is a discrete numerical data variable.
Watch for
A single answer such as “cat” is a value of the variable, not the variable itself.
Common mix-up
In algebra, a variable can stand for an unknown number. In data, a variable names a characteristic recorded across cases.
Exact meaning
A data variable is a characteristic measured, counted, or classified for each case or observation in a data set. Its possible values may be categorical or numerical, including discrete or continuous numerical values.