AP Statistics 2017

pair,   vertical    axis    is  the second

Shape —geometric description of a dataset: mound-shaped; symmetric, uniform; skewed; etc.

Significance level (α)—probability value that, when compared to the P -value, determines whether a
finding is statistically significant

Simple random sample (SRS) —sample in which all possible samples of the same size are equally likely
to be the sample chosen

Simulation —random imitation of a probabilistic situation

Skewed —distribution that is asymmetrical with data bunched at one end and a tail stretching out in the
other

Skewed left (right) —asymmetrical with more of a tail on the left (right) than on the right (left)

Spread —variability of a distribution

Standard deviation —square root of the variance;

Standard error —estimate of population standard deviation based on sample data

Standard normal distribution —normal distribution with a mean of 0 and a standard deviation of 1

Standard normal probability —normal probability calculated from the standard normal distribution

Statistic —measure that describes a sample (e.g., sample mean)

Statistical control —holding constant variables in an experiment that might affect the response but are not
one of the treatment variables

Statistically significant —a finding that is unlikely to have occurred by chance

Statistics —science of data

Stemplot (stem-and-leaf plot) —graph in which ordinal data are broken into “stems” and “leaves”;
visually similar to a histogram except that all the data are retained

Stratified random sample —groups of interest (strata) chosen in such a way that they appear in
approximately the same proportions in the sample as in the population

Subjects —human experimental units

Survey —obtaining responses to questions from individuals

Symmetric —data values distributed equally above and below the center of the distribution

Systematic bias —the mean of the sampling distribution of a statistic does not equal the mean of the
population; see unbiased estimate

Systematic sample —probability sample in which one of the first n subjects is chosen at random for the
sample and then each n th person after that is chosen for the sample

t -distribution —the distribution with n – 1 degrees of freedom for the t statistic

t statistic—