AP statistics unit 1

5Ws + H

who, when, where, why, what, how

sample

a portion of the entire population

population

the entire group

frequency

counts

relative frequency

percentages

segmented bar graph

stacked vertically

mosaic plot

like bar graph but frequency demonstrated by width

how to describe quantitative data

shape, center (, spread, special conditions

shape

unimodal, bimodal, multimodal, or uniform

symmetric, skewed left/right

center

median & mean

spread

standard deviation, variance

IQR, range

special conditions

clusters, outliers

5# summary

minimum, Q1, median, Q3, maximum, built for box-whisker plot

when comparing distributions, when both symmetrical…

use mean & SD

when comparing distributions, when both skewed…

median & IQR

when comparing distributions, when one symmetrical one skewed…

mean & IQR

shifting data

adding/subtracting the same number from each data value, shift the 5# summary and mean by that amount. IQR, range, SD, and shape stays the same.

scaling data

multiplying/dividing each value in a dataset by a constant, multiplies/divides the measures of position, mean, and measures of spread by that amount. The shape of the graph will stay roughly the same, but it will be scaled

empirical rule

68-95-99.7

z score =

(n - mean)/SD

z score to %

normalcdf(-99, z score) or (z score, 99)

% to z score

invNorm (percentage)