Statistics Fundamentals and Variable Categories

Flashcards covering the foundational definitions of statistics, including population vs. sample, parameters vs. statistics, and the classification of quantitative and qualitative variables.

Population

The totality of all subjects under study.

Sample

A group of subjects selected from within the population.

Variable

A characteristic of interest that varies from subject to subject, often formulated as the question being asked to obtain information.

Data

The actual information or survey results obtained from subjects.

Parameter

A number that summarizes and describes a characteristic or measure of a population; identified by the inclusion of the word all, such as all DAC students.

Statistic

A number that summarizes and describes a characteristic or measure of a sample.

Population Proportion

A parameter that describes a percentage for the entire population, such as the statement that $39\%$ of all DAC students are under a certain age.

Random Sample

A representative sample, such as choosing $200$ students randomly from different locations on campus, where every member has an equal chance of selection.

Quantitative Variable

A numerical variable that represents a characteristic that can be measured or counted.

Qualitative (Categorical) Variable

A variable where the data values are words or categories rather than numbers, such as a commute method like car, bus, or bike.

Discrete Variable

A quantitative variable consisting of whole counting numbers that does not include decimals, such as the number of days per week a student comes to campus ($0, 4, 1, 5, 2$).

Continuous Variable

A quantitative variable that can reach any desired level of accuracy and often includes decimals, such as describing commute distances as $8.4$ or $9.255$ miles.