| 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. | Weight, height, length, age, temperature in degrees Kelvin |
©Roger M. Palay
Saline, MI 48176
September, 2020