What is the difference between the interval scale and the ratio scale?

Answer 1

Interval scales have measurements which are in equal distance from each other. For example, the difference between 70 degrees and 80 degrees is 10, which is the same as the difference between 40 degrees and 50 degrees.

Ratio scales are similar to interval scales but include an absolute 0 measurement, which signifies the point when the characteristic being measured vanishes. For example, income (measured in dollars) at 0 means no income at all.

Basically, interval and ratio scales are the same, but ratio scales must be able to be measured at a zero starting point.

Answer 2

Interval scale does not have a natural zero (example time or temperature), and ratio has a natural zero (example weight or distance).