A characteristic of a population or sample (e.g. student grades)
Value
The value for a variable (e.g. students' marks from 0-100)
Data
The observed values of a variable (e.g. students' marked grades: 17, 99, 96, 100)
Cross-classification table
Listing the frequency of each combination of the values
Cross-classification tables show actual numbers
Relative frequency
How to interpret (e.g. graphing)
Hierarchy of data
Interval data - actual values that can be multiplied or subtracted (e.g. height, weight, prices)
Ordinal data - has a certain order or ranking, but cannot be multiplied or added (e.g. rating system: 1-poor, 2-fair, 3-good, 4-very good, 5-excellent)
Nominal data - categories with no order, cannot be multiplied or added (e.g. marital status: 1-single, 2-married, 3-divorced)
Interval data can be treated as ordinal or nominal
