Psychology
Introducing key terms -
Levels of measurement

Nominal data — The level of measurement that shows categories of data represented by frequencies. The data sets have no relative numerical value e.g. boys and girls.

Ordinal data — The level of measurement where data can be placed into ascending or descending order, but the intervals between data not necessarily equal e.g. the times for first, second and third in a race.

Interval data — The level of measurement that has equal numerical intervals between scores e.g. temperature. The interval between 1 and 2 degrees is the same as between 21 and 22 degrees.

Ratio data — The level of measurement that has equal intervals between scores and has an absolute or true zero point e.g. speed (mph)