Which scale of measurement has an absolute zero, except for one?

The ratio scale is indeed the correct answer as it possesses all the properties of the other scales of measurement, including an absolute zero point. An absolute zero indicates a complete absence of the quantity being measured, which means that zero signifies a true null value. For example, in a weight measurement, zero means no weight at all.

This scale allows for the comparison of absolute magnitudes and provides meaningful ratios. For instance, if one object weighs 10 kg and another weighs 5 kg, not only can we say that the first is heavier, but we can also say it is twice as heavy as the second.

In contrast, the ordinal scale ranks items but does not quantify the difference between them. The interval scale does have meaningful differences between values (like temperature in Celsius), but it lacks a true zero point—zero degrees does not mean the absence of temperature, just a point on the scale. The nominal scale, on the other hand, categorizes data without any numerical value, making it unsuitable for measuring magnitude or differences.

Thus, the ratio scale is unique in providing a true zero value and consistent, interpretable ratios, which is why it stands out in the context of measurement scales.