difference between interval and ratio
In an interval scale, subtraction is defined. In a ratio scale, division is defined. The classic example is the Celsius versus Kelvin temperature scales. On the Celsius scale, a difference of one degree is a meaningful quantity, but you can't say that 100 degrees Celsius is twice as hot as 50 degrees Celsius because the zero point is arbitrary.
In a ratio scale, you can take a ratio of two values. Example 40 kg is twice as heavy as 20 kg (taking ratios). Also, â0â on ratio scale means the absence of that physical quantity. â0â on interval scale doesn't mean the same.