ap stats chapter 1

individuals

objects descirbed by a set of data (‘WHO” is being measured)

variable

any characteristc of an individual (“WHAT” is being measured)

distribution

tells us what values a variable takes and how often it takes those values

frequency table

counts for each category of data

relative frequency table

a percent for each category of data

Name three ways to make a misleading graph

1. violating the area principle

2. vertical axis doesn’t start with zero

3. using pictures

marginal distributions

row and column totals (total of an individual category)

conditional distributions

relies on a condition

Data for categorical variables are displayed in a…

bar graph or pie chart

Data for quantitative variables are displayed in a…

dotplot, stemplot, or histogram

Bars in a bar graph…

DON’T touch

Bars in a histogram…

DO touch

In S.O.C.S., where do we use units?

Center, Spread, and Outliers

In S.O.C.S., where do we use comparison symbols?

Center and Spread

The mean is NOT a…

resistant measure of center

The MEDIAN is resistant to…

extreme data points

The mean and median will be close together…

if the distribution is roughly symmetrical

In a skewed distribution, the mean…

is pulled towards the long tail

What do we use for the CENTER if the distribution is ROUGHLY SYMMETRIC?

Mean

What do we use for the CENTER if the distribution is NON-SYMMETRIC?

Median

How can we identify outliers?

1.5 x IQR rule

lower bound outlier

Q₁ - 1.5 x IQR

upper bound outlier

Q₃ + 1.5 x IQR

What term do we use when interpreting the standard deviation?

“typically vary”

What do we use for the SPREAD if the distribution is ROUGHLY SYMMETRIC?

standard deviation

What do we use for the SPREAD if the distribution is NON-SYMMETRIC?

IQR