types of data

Qualitative (Categorical)

Data in words or labels, not numbers. Example: hair colour, blood type.

Quantitative (Numerical)

Data in numbers you can measure or count. Example: height, weight, test scores.

Discrete

Whole numbers only, countable. Example: number of siblings.

Continuous

Can take any value within a range. Example: height in cm, time in seconds.

Nominal

Categories with no order. Example: blood type (A, B, AB, O).

Ordinal

Ranked categories, but gaps aren’t equal. Example: satisfaction levels (happy, neutral, sad).

Interval

Numeric scale with equal spacing, but no true zero. Example: temperature in °C.

Ratio

Numeric scale with equal spacing and a true zero. Example: weight, age, height.

Primary Data

Collected firsthand by the researcher. Example: surveys, experiments.

Secondary Data

Already collected by someone else. Example: census, textbooks, databases.