Gegevensclassificatie: Categorische gegevens

Data, a scientific term used for the collection of observations and measurements, forms the basis for all the statistical analyses and inferences.

Data can be classified based on whether it can be measured or not. For example, consider different hair colors. One cannot measure hair color in liters or kilometers but instead can group them into categories such as black, brunette, or red.

Such data sets are called categorical data or qualitative data; they cannot be measured or counted but can be labeled or put into different categories.

Another example is human blood, which is grouped into four different types: A, B, O, or AB.

In certain cases, categorical data can be ordered in a particular fashion; such data are called ordinal categories. For example, the size of coffee cups—small, medium, large—or the height of trees in a forest—short, medium, tall—can be arranged in the order of increasing size.