Forholdstallnivået

Forholdstallnivået, often translated as "ratio level" or "proportion level" in English, refers to a specific concept within the context of psychological measurement and psychometrics. It is one of the four measurement scales proposed by Stanley Smith Stevens, alongside nominal, ordinal, and interval scales.

A ratio level of measurement is characterized by having a true zero point, meaning the absence of the attribute being measured. This true zero allows for meaningful ratios to be formed between measurements. For instance, a length of 10 meters is twice as long as a length of 5 meters, and a weight of 0 kilograms signifies no weight.

Key properties of ratio level data include:

1. **Classification:** Data can be categorized (like nominal).

2. **Order:** Categories have a meaningful order (like ordinal).

3. **Equal Intervals:** The distance between any two adjacent points on the scale is equal (like interval).

4. **True Zero:** A point exists where the attribute measured is completely absent.

Because of the true zero point, all arithmetic operations, including addition, subtraction, multiplication, and division, are meaningful with ratio level data. This makes it the most informative and versatile of Stevens' scales, allowing for the most sophisticated statistical analyses. Examples of ratio scale data include height, weight, age, income, and reaction time. It is crucial to identify the level of measurement when choosing appropriate statistical methods.