Unit 2Section 2-4

2-4: Other Types of Graphs

Several types of graphs are used in statistics besides histograms, frequency polygons, and ogives.

Other graphs include: Pareto Charts Time Series Graphs Pie Graphs

Pareto Charts

Pareto Chart – used to represent a frequency distribution for a categorical variable.

Frequencies are displayed by the height Bars are arranged from the highest to the lowest.

Tips for Drawing Pareto Charts Make the bars the same width. Arrange the data from largest to smallest according

to frequency. Make the units that are used for the frequency equal

in size.

Section 2-4

Activity: Pareto Chart Create a Pareto Chart using the

following info:Average Cost Per Mile for Passenger

Vehicles on State Turnpikes

Section 2-4

State Number

Indiana 2.9 cents

Oklahoma 4.3 cents

Florida 6.0 cents

Maine 3.8 cents

Pennsylvania 5.8 cents

Time Series Graph

Time Series Graph– represents data that occurs over a specific period of time.

Tips for Time Series Graph Draw and label the x and y axes. The x axis usually represents time, the y axis

an amount. Plot each point according to the table. Draw line segments connecting adjacent

points.

Section 2-4

Activity: Time Series Graph Create a Time Series Graph using

the following info:The Number (in millions) of Vehicles That

Used the Pennsylvania Turnpike:1999-2003

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Year Number

1999 156.2

2000 160.1

2001 162.3

2002 172.8

2003 179.4

Pie Graph

Pie Graph– a circle that is divided into sections or wedges according to the percentage of frequencies in each category of the distribution.

Tips for Drawing Pie Graphs Determine the degree measure for each piece of

the pie. Take the frequency, divide it by the sum of the frequencies,

then multiply it by 360 degrees. Determine the percentage for each piece of the pie. Create the graph

Section 2-4

Activity: Pie Graph Create a Pie Graph using the

following info:Pounds of Snacks Eaten During the Super

Bowl

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Snack Pounds (Frequency)

Potato Chips 11.2 million

Tortilla Chips 8.2 million

Pretzels 4.3 million

Popcorn 3.8 million

Peanuts 2.5 million

Stem and Leaf Plot

Stem and Leaf Plot– data plot that uses part of the data values as the stem and part of the data values as the leaf to form groups or classes.

Tips for Drawing Stem and Leaf Plot Arrange the data in order. Separate data according to the first digit shown. The first digit becomes the “stem” and the trailing

digit(s) becomes the “leaf” i.e. for the number 14, 1 is the stem and 4 is the leaf.

Section 2-4

Activity: Stem and Leaf Plot Create a Stem and Leaf plot using

the following info:Number of Cardiograms Performed Over

20 Days

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25 31 20 32 13

14 43 02 57 23

36 32 33 32 44

32 52 44 51 45

Homework Pg 87 & 88: 1, 2, 7, 8, 21

Pg 89 & 90: 1 - 11

Section 2-4