Displaying Distributions With Displaying Distributions With GraphsGraphs

Section 1.1Section 1.1

A Picture is worth a thousand A Picture is worth a thousand wordswords

First three rules for describing data:First three rules for describing data:– Make a pictureMake a picture– Make a pictureMake a picture– Make a pictureMake a picture

Categorical DataCategorical Data

The following table displays the sales The following table displays the sales figures and market share (percent of total figures and market share (percent of total sales) achieved by several major soft drink sales) achieved by several major soft drink companies in 1999. That year a total of companies in 1999. That year a total of 9930 million cases of soft drink were sold.9930 million cases of soft drink were sold.

CompanyCompany Cases Sold Cases Sold

(Millions)(Millions)

Market ShareMarket Share

(percent)(percent)

Coca-ColaCoca-Cola 4377.54377.5 44.144.1

Pepsi-ColaPepsi-Cola 3119.53119.5 31.431.4

Dr. Pepper/7-upDr. Pepper/7-up 1455.11455.1 14.714.7

Cott Corp.Cott Corp. 310.0310.0 3.13.1

Nat. Bev.Nat. Bev. 205.0205.0 2.12.1

Royal CrownRoyal Crown 115.4115.4 1.21.2

OtherOther 347.5347.5 3.43.4

Creating a Bar GraphCreating a Bar Graph

Title your graphTitle your graph

Label axesLabel axes– Horizontal Axis is the categoriesHorizontal Axis is the categories– Vertical Axis can beVertical Axis can be

Counts (Frequency)Counts (Frequency)

Proportions (Relative Frequency)Proportions (Relative Frequency)

PercentsPercents

Scale your axesScale your axes

Draw vertical bars to represent counts, Draw vertical bars to represent counts, proportions, or percentsproportions, or percents

1999 Soft Drink Sales-Market Shares

0500

100015002000250030003500400045005000

Coca-

Cola

Pepsi-

Cola

Dr. Pep

per/7

-up

Cott C

orp

Nat. B

ev.

Royal

Crown

Oth

er

Company

Cas

es S

old

(milli

ons

Creating a Pie GraphCreating a Pie Graph

The most accurate way to create a pie The most accurate way to create a pie graph is to use a computer. However pie graph is to use a computer. However pie graphs can be created using estimation, or graphs can be created using estimation, or by using a protractor and using the by using a protractor and using the appropriate number of degrees to create appropriate number of degrees to create the graph.the graph.

1999 Soft Drink Sales-Market Shares

44%

31%

15%

3%

2%

1%

4%

Coca-Cola

Pepsi-Cola

Dr. Pepper/7-up

Cott Corp

Nat. Bev.

Royal Crown

Other

Bar Graphs show a bar that represents Bar Graphs show a bar that represents either the count, proportion, or percentage either the count, proportion, or percentage of each category. Bar graphs may or may of each category. Bar graphs may or may not show all categories.not show all categories.

Pie Graphs show how a “whole” divides into Pie Graphs show how a “whole” divides into categories using either the proportion or categories using either the proportion or percentage. To use a pie graph you must percentage. To use a pie graph you must include include allall the categories that make up the the categories that make up the whole.whole.

Further ResourcesFurther Resources

Practice of Statistics: pg 8-9Practice of Statistics: pg 8-9

Homework 1.1: #2Homework 1.1: #2