Types of Variation
Attributes, or qualitative variables, can be scored, but not fall into a continuum.
Examples: human eye color, political party, blood type, gender, etc..
Quantitative, or measurable, variables fall along a measurable axis, and can be measured to observe their place relative to others.
Discontinuous measurable variables: fall into discrete intervals. Examples: shoe size, number of mates, number of arrests for drunk driving, etc..
Continuous measurable variables do not fall into discrete intervals, they exist along a continuum. Examples: height, weight, age, etc..