AP Statistics Exam Review

discrete variables

listable sets (counts)

continuous variables

any value over an interval of values (measurements)

SOCS

shape

outliers

center

spread

center

mean, median, and mode

spread

variability

(range, standard deviation, IQR)

interquartile range (IQR)

Q3-Q1

mean (μ)

population (parameter)

mean (x)

sample (statistic)

standard deviation (σ)

population (parameter)

standard deviation (s)

sample (statistic)

standard deviation

average amount of variability in the data set;

how far each score lies from the mean

resistant (not affected by outliers)

median

IQR

skewed right (mean & median)

mean is a larger value than median

skewed left (mean & median)

mean is smaller than median

z-score

standardized score used to tell you how many standard deviations from the mean an oberservation is

z-score μ = ?

0

z-score σ=?

1

empirical rule

68

95

99\.7

residuals sum

0

residual formula

actual y value - predicted y value

extrapolation

when we predict values for points outside the range of data taken

stratified sample

divide the population into homogeneous groups called strata, then simple-random-sample each strata

cluster sample

based on location

select a random location and sample ALL of that location

confidence intervals

used to estimate the unknown population parameter

margin of error

the degree of error in results received by random sampling surveys

robust

if the assumption of normality is not met, the confidence level or p-value does not change much

null hypothesis

H0 is the statement being tested

“no effect” “no difference” or “no relationship”

alternate hypothesis

Ha is the statement suspected of being true

p-value

assuming the null is true, the probability of obtaining the observed result or more extreme

level of significance

a is the amount of evidence necessary before rejecting the null hypothesis