Data Types

Nominal

• Items being measured have something in common
• Not measurable in terms of numbers
• Example: fruit-apples, pineapples, strawberries, etc.
• Not valued as one more than the other

Ordinal

• Order matters but not the difference between values
• order of items is often defined by assigning numbers to them to show their relative position
• Example: winners in a race, first, second, third (although the first runner may have won 3 minutes faster than the second and the second may have only beat the third by 1 second)
• Likert scales

Interval

• A measurement where the difference between two values is meaningful
• Example: The difference between a temperature of 100 degrees and 90 degrees is the same difference as between 90 degrees and 80 degrees
• Each position is equidistant from one another, allowing for the distance between two pairs to be equivalent.

Ratio

• All the properties of an interval variable, and also has a clear definition of 0.0
• Examples: height, weight, temperature (Kelvin)
• Scale data, quantitative