Statistics Definitions > Ratio Scale / Ratio Data

## What is a Ratio Scale?

A ratio scale has all the properties of an interval scale. Ratio data on the ratio scale has measurable intervals. For example, the difference between a height of six feet and five feet is the same as the interval between two feet and three feet. Where the ratio scale differs from the interval scale is that it also has a**meaningful zero**. The zero in a ratio scale means that something doesn’t exist. For example, the zero in the Kelvin temperature scale means that heat does not exist at zero. Other examples of the ratio scale:

- Age. The clock starts ticking when you are born, but an age of “0” technically means you don’t exist.
- Weight. At 0 pounds, you would weight nothing and therefore wouldn’t exist.
- Height. If you were 0″, you would have no height.
- Sales figures. Sales of zero means that you sold nothing and so sales didn’t exist.
- Quantity purchased. If you bought 0 items, then there were no quantities purchased.
- Time measured from the “Big Bang.”

### The Ratio Scale and Negative Numbers.

As the “0” in the ratio scale means the complete absence of anything, there are no negative numbers on this scale.

### The Ratio Scale and Ratios.

As the name suggests, we can create meaningful ratios between numbers on a ratio scale.

For example, a count of how many tests you took last semester could be zero if you didn’t take any tests. However, if you took two exams this semester and four the last semester, you could say that the frequency of your test taking this semester was half what it was last semester.

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