AP stats unit 1

define indivduals

person or thing described in set of data

define variables

attribute for individuals

define categorical variables

types and labels for responses

define quantitative variable

number-based responses, where a mean makes sense

equation for finding the whole with a part

%*(T)=P

T= total

P=part

how to show what a percentage of a variable in data is

P(a)=%

a=variable

How to show the percentage of 2 or more variables

P(AnB)=%

A and B= variables

n= and

How to show precentage of one thing given another (conditional probability)

P(a|b)=%

|=given that

A and B= variables

∩ =

intersection

∪ =

union

Bar graph are used for what kind of data

categorical

In bar graphs, the bars are…

not connected

You should use relative frequency instead of frequency when…

comparing 2 groups of different sizes

in side by side and segmented bar graphs, the x axis is…

explanatory

in side by side and segmented bar graphs, the y axis is…

response

do not use pie charts when..

individuals can fit into multiple categories

y axis should always…

start at 0.

In stem and leaf plots, one must always..

add a key

In histograms, there are no

gaps between bars

In histogram bars, the left side is __ and the right is _

included, excluded

define discrete data:

countable, not measureable (inf. sig-figs)

define continous data

infinate # of values, anything someone meaures phyically

for describing data, use the acronym:

SOCS

S=

shape

how to know which side a graph is skewed on

whichever side tails off

1 peak=

unimodal

2 peaks=

bimodal

evenly ish height=

uniform

always include ___ when describing a graph

context

O=

outlier

equation for high outlier:

Xi > Q3 + 1.5(IQR)

equation for low outlier:

Xi < Q1 -1.5(IQR)

Atl. outlier rule:

x̄ ± 2(Sx)

If there’s a question asking if there are any outliers…

You must prove there are or are not by testing both high and lowest values. Then prove by writing if it is or isn’t greater or less than ___.

C=

center

To find rank number of the median..

(n+1)/ 2

M=

population mean

x̄ =

sample mean

equation for mean:

x̄= 1/n ∑ xi

S=

spread

IQR=

Q3- Q1

Q1 and Q3 are

the medians of each half of data

IQR describes

how spread the middle 50% values are

Sx=

sample standard deviation

Sx equation:

σ=

population standard dev.

When describing Sx, say…

The typical individual varies from the mean by Sx amt.

For skewed date, use:

median and IQR

for symettric data, use

mean and standard deviation

generally, when mean> median…

skewed right

generally, when mean< median…

skewed left

define statistic…

data on a sample

define parameter…

data on a population

Order of 5-number summary:

(min, Q1, med, Q3, max)

Box plots break data into..

quarters

box plots do a bad job at..

showing the shape of the data