Discrete and continuous variables
A variable is a quantity whose value is not a constant.
A quantitative variable is a variable whose possible values are numeric.
A qualitative variable is a variable whose possible ‘values’ are non-numeric.
Examples of quantitative variables:
the thickness of a piece of glass, the number of patients staying in a hospital
Examples of qualitative variables:
colour of a flower, opinion on a new regulation
make, colour, brake system
Discrete quantitative variable:
A discrete variable is a quantitative variable which can take up isolated values only.
A continuous variable is a quantitative variable which can take up any value within a certain
A, B, C, D, E, F, U
0, 1, 2, . . . , 40
0, 1, 2, 3, . . .
are shown in the following table:
Blood type (A)
A, B, AB, O
Catholic, Christianity, Islam,
Whether a smoker (F)
Whether agree to ban
Agree, Not agree