What is the difference between nominal and ordinal data?

• A. Both have order
• B. Nominal has no inherent order; ordinal has an inherent order
• C. Nominal has order; ordinal has no order
• D. Neither has order

Answer: (B)

The difference lies in whether category labels can be arranged in a meaningful sequence. Nominal data classify into categories with no intrinsic ranking—think blood type (A, B, AB, O) or species. You can count how many fall into each category, but you can’t say one category is higher or lower than another. Ordinal data, on the other hand, have a natural order among categories—such as pain levels (none, mild, moderate, severe) or cancer stages (I to IV). You can rank individuals or observations, but you shouldn’t assume the distance between adjacent levels is the same.

That’s why this statement is the correct one: nominal data have no inherent order, while ordinal data do have an inherent order. The other ideas would misclassify the nature of these data types, suggesting order where there isn’t any or denying order where it exists.