Which data type is missing from the list below?
CHARACTERISTICS OF VARIABLES
Ratio data Has a natural zero point and can take any value upwards.
Difference and ratio between any two scores is meaningful.
Interval data Can take any value upwards, but has no natural zero point.
Difference between any two scores is meaningful, but not their ratio.
Ordinal data Indicates only rank in a series.
Differences not mathematically meaningful.
eg. age groups
Categorical data Datapoint is a number that represents membership of a category.
Number has no mathematical value.
eg. gender (1=male, 2=female)