AP Statistics - Chapter 2

percentile

The percentage of observations less than or equal to this observation.

cumulative relative frequency graph

A graph that plots a point corresponding to its corresponding percentile, and then joins the points together with a line.

standardized score

How many standard deviations an observation falls from the mean. z=(value-mean)/standard deviation.

transforming

Converts the original observation to another scale.

density curve

A curve that is always greater than or equal to 0, has an area under the curve of exactly 1, and the area of any interval is the probability of an observation falling in that interval.

normal curve

A symmetric, single-peaked, bell-shaped density curve that can approximate many kinds of chance outcomes.