Discrete" finite or fixed number of values)grades_'
continuous:" infinite number of values )te,perature_
nominal: categorical data (eye color; six, ethnicity)
ordinal: ordered categorical data, differences between values are not important (restaurant ratings; opinion polls)
interval data: ordered continuous data with a constant scale, but no natural zero (temperature)
differences can be calculated, but rtios are problematic.
ratio data: ordered continuous data with a constant scale and natural zero (geight, weight, age, length).

how they are measured matters in how they are mapped.