Which scale would you use to categorize people by blood type?

Which scale would you use to categorize people by blood type?

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

Answer: (A)

Categorizing people by blood type involves labeling individuals into named categories that have no inherent order. This is a nominal scale, used for assigning labels without any ranking or equal intervals between categories. You can identify someone as A, B, AB, or O, but you cannot say one category is greater than another or quantify a difference between them. There’s no meaningful zero point either, which rules out ratio concepts. An ordinal scale would require an order (like small, medium, large), which blood types don’t have. Interval and ratio scales require meaningful distances between values and, for ratio, a true zero—neither of which applies to mere labels for blood types.

Categorizing people by blood type involves labeling individuals into named categories that have no inherent order. This is a nominal scale, used for assigning labels without any ranking or equal intervals between categories. You can identify someone as A, B, AB, or O, but you cannot say one category is greater than another or quantify a difference between them. There’s no meaningful zero point either, which rules out ratio concepts.

An ordinal scale would require an order (like small, medium, large), which blood types don’t have. Interval and ratio scales require meaningful distances between values and, for ratio, a true zero—neither of which applies to mere labels for blood types.