AP STATS 1.1-1.2

Descriptive statistics

Organize and summarize the data that were observed

Statistical inference

Use sample data to draw conclusions about a larger population while acknowledging uncertainty.

Datum

One piece of information about an item or individual

Data set

A collection of data

Population

All items or individuals of interest; denoted by N.

Sample

The subset of the population from which data are obtained; its size is denoted by n.

Census

Data collected from every item or individual in the population.

Observational unit

An item or individual from which a datum is collected.

Variable

A characteristic that may change from one observational unit to another.

Categorical (qualitative)

Values are category names or group labels

Quantitative (numerical)

Values are measured or counted quantities for which arithmetic has meaning.

Discrete quantitative

Possible values are countable, such as a number of absences.

Continuous quantitative

Any value in an interval is possible, such as height or time.

Parameter

A numerical attribute or summary of a variable for a population. It’s value is usually unknown.

Statistic

A numerical attribute or summary of a variable for a sample. It is calculated from observed data and can be used to estimate a parameter.