Interval scale

Definition

An interval scale is a level of measurement where the difference between values is meaningful and consistent, but there is no true zero point. Examples include temperature in Celsius or Fahrenheit and IQ scores.

5 Must Know Facts For Your Next Test

1. Interval scales allow for the calculation of means and standard deviations.
2. The differences between values on an interval scale are interpretable and equal.
3. Interval scales do not have a true zero point, meaning ratios are not meaningful.
4. Temperature in Celsius or Fahrenheit is a common example of an interval scale.
5. Arithmetic operations such as addition and subtraction can be performed on interval data.

Review Questions

• Why can't you use ratio comparisons with interval scale data?
• What makes an interval scale different from an ordinal scale?
• Give two examples of variables that are measured on an interval scale.

Related terms

Nominal Scale: A level of measurement used for labeling variables without any quantitative value. Examples include gender, nationality, and color.

Ordinal Scale: A level of measurement where variables have ordered categories, but the intervals between them are not necessarily equal. Examples include ranking preferences or levels of education.

Ratio Scale: A level of measurement with all properties of an interval scale, plus a true zero point. Examples include weight, height, and income.