AP Statistics 1A

Parameter

A number that describes some characteristic of a population

Statistic

A number that describes some characteristic of a sample

Observational Unit

An item or individual described in a data set or a statistical study

Variable

A characteristic that can take different values for different observational units

Discrete Quantitative

A variable that can take a set of possible values with gaps between them on the number line.

Discrete continuous

A variable can take any value in an interval on the number line; generally measurements and time

Frequency

The number of observational units having each value of a variable

Relative Frequency

A table that shows the proportion or percentage of observational units having each value of a variable

Bar graph

graph of data for one categorical variable that displays each category as a bar.

Histogram

graph of data for one categorical variable in each of two or more groups that displays a separate bar corresponding to each group for every category.

Dotplot

graph of data for one quantitative variable that displays each data value as a dot above its location; should be used for smaller sets of quantitative data

CUSS with context C

center, median, mean mode, “midpoint”

CUSS with context U

unusual, gaps, outliers, clusters, etc.

CUSS with context first S

shape, approx. symmetrid, uniform, skewed left, skewed right,

CUSS with context, second S

spread, variability

What are averages

continuous

TLLTT

title, label, label, tick, tick