Which scale allows comparisons between numbers with a true zero point?

The ratio scale is the correct answer because it is characterized by the presence of a true zero point, which indicates an absence of the quantity being measured. This allows for meaningful comparisons and calculations, including the ability to express one value as a multiple of another. For example, with a ratio scale, you can say that length of 10 meters is twice as long as 5 meters since zero truly means 'no length.'

In contrast, the nominal scale categorizes data without any numeric value or order, making comparisons impractical since there is no inherent relationship between the categories. The ordinal scale provides a rank order for the data, but it does not allow for the determination of the actual differences between the ranks, and it also lacks a true zero. The interval scale does allow for comparisons and differences between values, but it does not have a true zero point; for instance, a temperature of 0 degrees does not indicate the absence of temperature, making it less fitting for ratio comparisons.

Overall, the ratio scale uniquely supports robust mathematical operations, including multiplication and division, due to its true zero point, setting it apart from the other scales.