Before selecting a statistical test, it's important to understand the types of data you are dealing with. Data can be classified into four main types:
1. Nominal Data: Categorical data without a specific order (e.g., blood type, gender). 2. Ordinal Data: Categorical data with a defined order but unequal intervals (e.g., pain scale ratings). 3. Interval Data: Numerical data with equal intervals but no true zero (e.g., temperature in Celsius). 4. Ratio Data: Numerical data with a true zero (e.g., weight, height).
