A nominal variable
Definition: is for mutual exclusive, but not ordered, categories.
Example: Gender male/female
Statistical-
Methods: T-test, Chi
Techniques: Mode
An ordinal variable
Definition: is one where the order matters but not the difference between values.
Ranking, tall-small
Example: start of a hotel, ranking the happy you feel, 1=not happy, 5=very happy
Statistical-
Methods: T-test, Chi
Techniques: Mode, Median
An interval variable
Definition: is a measurement where the difference between two values is meaningful.
The difference between a temperature of 100 degrees and 90 degrees is the
same difference as between 90 degrees and 80 degrees.
Example: temperature
Statistical-
Methods: T-test, Correlation
Techniques: Mode, Median, Mean, SD
A ratio variable
Definition: all the properties of an interval variable, but also has a clear definition of
0.0. When the variable equals 0.0, there is none of that variable.
Example: Age
Statistical-
Methods: T-test, Correlation, SD
Techniques: Mode, Median, Mean, SD