Interval scale

Definition

An interval scale is a level of measurement where the distance between any two adjacent values is equal, but there is no true zero point. Examples include temperature in Celsius or Fahrenheit and dates on a calendar.

5 Must Know Facts For Your Next Test

1. Interval scales allow for the comparison of differences between values, but not for ratios because there is no true zero point.
2. Arithmetic operations like addition and subtraction are meaningful with interval data.
3. Common statistical measures such as mean and standard deviation can be computed with interval data.
4. Interval scales are more informative than nominal and ordinal scales but less so than ratio scales.
5. Examples of interval data include IQ scores, SAT scores, and dates (e.g., years).

Review Questions

• What distinguishes an interval scale from a ratio scale?
• Why can't ratios be meaningfully calculated with interval data?
• Give two examples of measurements that use an interval scale.

Related terms

Nominal Scale:

A level of measurement used for labeling variables without any quantitative value. Examples include gender, nationality, or hair color.

Ordinal Scale:

A level of measurement where values can be ordered or ranked, but the distances between the values are not known. Examples include class rankings or levels of satisfaction.

Ratio Scale:

$\text{A level of measurement that has all the properties of an interval scale, along with a true zero point. Examples include weight, height, and time duration.}$