Behavioral Statistics: Variables and Their Distributions

Vocabulary practice flashcards covering variable types, measurement scales, summary statistics, tabling, graphing conventions, and statistical classifications.

Variable

A measurement or characteristic that can take on more than 1 possible value across observations in a dataset.

Distribution

A presentation of a variable listing all of its possible values alongside a summary measure (such as frequency) computed for each value.

Nominal Scale

A scale of measurement consisting of qualitative, non-ordered categories, such as gender, hair color, or college major.

Ordinal Scale

A scale of measurement consisting of ordered categories where relative rank is meaningful, such as letter grades or word pleasantness ratings on a $1\text{--}7$ scale.

Interval Scale

A scale of measurement characterized by equal intervals between values but lacking a true zero point, such as temperature in Fahrenheit.

Ratio Scale

A scale of measurement featuring equal intervals between values and a true zero point, such as percentage correct on an exam or elapsed time in seconds.

Frequency

A summary statistic representing the direct count of observations falling into a specific category.

Proportion

A summary statistic calculated as category frequency divided by total sample size ($\text{frequency}/N$), useful for comparing different datasets.

Conditional Proportion

A summary statistic calculated as category frequency divided by a subgroup subtotal ($\text{frequency}/\text{subtotal}$), used to compare subgroups within the same dataset.

Cumulative Frequency

A summary statistic representing the running total of frequencies across successive categories up to a given cut-point.

Cumulative Proportion

A summary statistic representing the running total of proportions across successive categories up to a given cut-point.

Class Interval

A mutually exclusive range of scores constructed to group adjacent values together when summarizing continuous interval or ratio scale variables with many unique values.

Bar Graph

A graphical representation with visible gaps between adjacent bars along the x-axis, used to display distributions of nominal and ordinal scale variables.

Histogram

A graph with contiguous (touching) bars used for continuous interval or ratio scale variables, where x-axis labels typically represent class interval midpoints.

Polygon

A line graph used for continuous interval or ratio scale variables where data points are plotted above class interval midpoints, connected by lines, and anchored to zero on both ends.

Descriptive Statistics

Methods used to summarize, organize, and describe key features or overall trends of a collected dataset using tables, graphs, typical values, or measures of variability.

Univariate Statistics

Statistical procedures involving the analysis and presentation of a single variable at a time, such as means, variances, and frequencies.

Bivariate Statistics

Statistical procedures involving the analysis of the relationship between two variables simultaneously, such as correlation and regression.

Inferential Statistics

Statistical procedures used to draw conclusions or make generalizations about a broader population based on data collected from a sample.

Classification of Behavioral Statistics

The organizational hierarchy dividing statistical methods into univariate (means, variances, frequencies) and bivariate (correlation, regression) statistics, each subdivided into descriptive and inferential categories.