Levels of Measurement & Related Concepts

Flashcards cover populations, samples, parameters, statistics, descriptive vs. inferential statistics, conceptual vs. operational definitions, levels of measurement (nominal, ordinal, interval, ratio), data types (qualitative vs quantitative), sampling concepts, and example applications from the lecture.

Population

The entire set of individuals of interest in a study.

Sample

A subset drawn from a population, intended to represent the population; often a convenience sample in lab experiments.

Parameter

A numerical value describing a population (e.g., population mean).

Statistic

A numerical value calculated from a sample (e.g., sample mean).

Descriptive Statistics

Describe a sample using measures such as frequency counts, means, and standard deviations.

Inferential Statistics

Use sample data to make inferences about populations (e.g., t-tests, ANOVAs, correlations, chi-square).

Conceptual Variable

An abstract concept that cannot be directly measured (e.g., fear in rats).

Operational Definition

A concrete, observable indicator used to measure a conceptual variable (e.g., seconds spent freezing).

Nominal Level of Measurement

Qualitative; uses numbers as labels for categories; has no intrinsic order (e.g., gender, color).

Ordinal Level of Measurement

Categories with a meaningful order, but with distances between categories not necessarily equal.

Interval Level of Measurement

Quantitative; equal intervals between values; no true zero, so ratios are not meaningful.

Ratio Level of Measurement

Quantitative; equal intervals and a true zero point; ratios of scores are meaningful.

Discrete Variable

A variable with a finite number of possible values that can be counted.

Continuous Variable

A variable with infinitely many possible values within a given range.

Qualitative Data

Non-numeric, descriptive data.

Quantitative Data

Numeric data that can be measured or counted.

Representative Sample

A sample that closely reflects the population's key characteristics.

Convenience Sample

A nonrandom sample chosen for ease of access, often less representative.

Frequency Distribution

A summary showing how often each category or value occurs in the data.

Table

A structured display used to present data and frequency distributions.

HOLE BOARD TEST (Level of Measurement)

Ordinal: data can be ranked, but the distances between categories (holes) are not guaranteed to be equal.

Levels of Measurement Summary

Nominal: qualitative; Ordinal: qualitative with order; Interval: quantitative with equal intervals; Ratio: quantitative with true zero.

Take-home message about Levels of Measurement

The same variable can be measured at different levels depending on what is measured and how the experiment is designed.

Example: Exercise data levels

The same variable (exercise) can be measured at nominal, ordinal, interval, or ratio levels depending on the measurement chosen.