Kinds of data

Kind	Explanation	Examples
Nominal	A number or value is just used as a name.	Phone number, student number, credit card number, or cases where we assign numbers to things just to group them
Ordinal	Numbers are assigned to things but, in addition to a name, the numbers provide a meaningful order.	Opinion questionnaires, rankings
Interval	Numbers are assigned by a reliable, verifiable/valid measurement, one with consistent steps but without a true 0.	Temperature in degrees Fahrenheit or degrees Celsius
Ratio	Numbers are assigned by a reliable, verifiable/valid measurement, one with consistent steps and a true 0.

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Reliable: repeated measures give almost identical results

Verifiable/Valid: other ways to determine the value yield similar results