What is the defining characteristic of a ratio scale?

A ratio scale is characterized by its ability to measure variables that have all the properties of an interval scale, combined with the presence of a true zero point. This true zero allows for meaningful comparisons of absolute magnitudes. For instance, when measuring height, weight, or time, the zero point indicates the absence of the quantity being measured, making it possible to say that an object that is 10 kilograms is twice as heavy as another object that is 5 kilograms.

This makes ratio scales particularly useful in quantitative analysis since they allow for a full range of mathematical operations, including division, which is not possible with other scale types that lack a true zero. While interval scales can measure differences and allow for ranking, they do not support the concept of an absolute zero, limiting the types of comparisons that can be meaningfully made. The other options relate to scale types that either address qualitative data (which ratio scales do not), focus solely on ranking without precise measurement (like ordinal scales), or deal primarily with categorical distinctions, which are outside the realm of ratio scales.