Nominal vs Categorical
Aspect | Nominal Data | Categorical Data |
|---|---|---|
Meaning | A type of data that names or labels categories without any order or ranking. | A broader term that includes all data divided into categories, including both nominal and ordinal types. |
Order / Ranking | No natural order among categories. | May or may not have order (depending on type — nominal or ordinal). |
Examples | Gender (Male/Female), Blood group (A, B, AB, O), Type of drug (Aspirin, Paracetamol). | Nominal: same as left. Ordinal (also categorical): Pain level (Mild, Moderate, Severe), Satisfaction (Low, Medium, High). |
Type of Variable | Always qualitative (non-numeric). | Includes qualitative variables (nominal + ordinal). |
Statistics Used | Mode, frequency, percentage. | Same, but if ordinal — median and nonparametric tests may apply. |
🔹 In short:
Categorical data → the general group of data divided into categories.
Nominal data → a subtype of categorical data with no order.
✅ Example:
If “Patient condition” = Mild, Moderate, Severe → categorical (ordinal).
If “Blood type” = A, B, AB, O → categorical (nominal).