Which scale has ordered categories with equal intervals and a true zero point?

Which scale has ordered categories with equal intervals and a true zero point?

• A. Ratio Scale
• B. Interval Scale
• C. Ordinal Scale
• D. Nominal Scale

Answer: (A)

The main idea here is recognizing scales that preserve both meaningful zero and equal spacing between values, which allows meaningful ratios. The ratio scale has all of this: it orders observations, the intervals between successive values are equal, and zero represents the absence of the quantity. Because zero means “none,” you can compare values with multiplication and division (one value can be twice another, etc.). Examples include height, weight, and time durations measured from a true zero point. In contrast, an interval scale has equal intervals but an arbitrary zero (zero does not represent the absence of the quantity), so ratios aren’t meaningful—10 minus 0 equals 10, but 20 is not "twice" 10 in a meaningful sense. An ordinal scale only preserves order, not equal distances between levels, so you can say which is larger but not by how much. A nominal scale categorizes data without any inherent order or distance between categories. Thus, the scale that fits all parts of the description is the ratio scale.

The main idea here is recognizing scales that preserve both meaningful zero and equal spacing between values, which allows meaningful ratios. The ratio scale has all of this: it orders observations, the intervals between successive values are equal, and zero represents the absence of the quantity. Because zero means “none,” you can compare values with multiplication and division (one value can be twice another, etc.). Examples include height, weight, and time durations measured from a true zero point.

In contrast, an interval scale has equal intervals but an arbitrary zero (zero does not represent the absence of the quantity), so ratios aren’t meaningful—10 minus 0 equals 10, but 20 is not "twice" 10 in a meaningful sense. An ordinal scale only preserves order, not equal distances between levels, so you can say which is larger but not by how much. A nominal scale categorizes data without any inherent order or distance between categories.

Thus, the scale that fits all parts of the description is the ratio scale.