Variable Types

Nominal: Categorical variables whose values are not arithmetically relevant. A nominal variable might be "race" or "religion"; the categories of these variables cannot be ordered or compared using math. We do not say that one is more Methodist than another.

Ordinal: These variables show difference by degree; they follow an ordered list. We might ask whether opinions of the use of nuclear technology and allow agree, indifferent or disagree as responses. This ordinal variable would allow us to say that one is more opposed to the use of that technology than another.

Interval/Continuous: These are arithmetically relevant variables such as GDP per capita and income. Mathematically comparisons can easily be applied to these data to better understand them (i.e. X is twice Y). Rates are a very common form of continuous variable