What is the main characteristic of a ratio variable compared to an interval variable?

The main characteristic that distinguishes ratio variables from interval variables is that ratio variables allow for meaningful interpretation of ratios. This means that with ratio variables, not only can you quantify the difference between values (as you do with interval variables), but you can also compare the magnitudes of these values.

For example, if you have a ratio variable like weight, you can say that one object is twice as heavy as another because their values can be meaningfully divided (e.g., 4 kg is twice 2 kg). The existence of a true zero point—where a value of zero indicates the absence of the quantity being measured—is also inherent in ratio variables, which is not necessarily the case for interval variables.

Other characteristics that help differentiate ratio variables include that they can take on a range of values (including negatives in some contexts, but not in terms of traditional measurements like weight) and that they are not restricted to whole numbers.