Also known as attributes or features…
The values of numerical variables are numbers. Numerical variables are:
Continuous, meaning that they can take any value within a given range, including fractions. A measurement of distance is a good example.
Discrete, meaning that they have a fixed set of acceptable values in a range. Shoe sizes or number of children are good examples.
The values of categorical variables are text. Categorical variables are:
Ordinal, meaning the values have a natural order; there is a concept that one value is “bigger” than another. An example might be the values small, medium and large.
Nominal, meaning the values have no natural order. Types of animal are an example: a variable could have the values dog, cat, or mouse, but there is no way to sort those into any meaningful order.
