Statistical Methods in Psychology (PSY3204-C): Levels of Measurement

Population

A complete set of people with a specialized set of characteristics

Parameter

An analysis of the population

Sample

The subset of the population

Statistic

An analysis of the sample

Variable

A condition or characteristic that can have
different values

Value

A possible number or category that scores can have

Score

A particular person’s score on a variable

Level of Measurement

A type of underlying numerical information provided by a measure

Quantitative Data

Numerical; answers questions about “how many” and “how much”

Qualitative Data

Descriptive and non-numerical; answers questions about the “why” or “how” behind a phenomenon

Ratio Data

Quantitative data where a true zero exists within the differences between measurements

Interval Data

Quantitative data where no true zero exists within the differences between measurements; zero is arbitrary

Ordinal Data

Qualitative data that has ordered categories by ranking, order, or scaling

Nominal Data

Qualitative data with unordered categories

Equal Interval

Data where the difference between numbers anywhere on a scale is the same

Continuous Numbers

Infinite values between points

Discrete Numbers

Specific values between points

Example of Ratio Data

Temperature in Kelvin

Example of Interval Data

Personality tests

Example of Ordinal Data

Olympic medals

Example of Nominal Data

Car brands