Dealing with Data

Understanding Graphs

Food Votes

Pizza 972

Hot Dogs 987

Hambur-gers 955

1. A survey was taken to show people’s favorite foods. Which graph is a fairer representation of the data? Why?

Eric Curts, North Cantonwww.northcanton.sparcc.org/~technology/excel/index.html

2. The graphs show the growth in the use of cell phones. They used the same data. Why do the graphs look different? Which better explains the data.

http://www.glencoe.com/sec/math/prealg/prealg03/extra_examples/chapter12/lesson12_5.pdf

3. This appeared in the Winnipeg Free Press.

Is the headline correct or is the graph correct?

http://www.math.sfu.ca/~cschwarz/Stat-301/Handouts/node14.html

4. How could this graph be better?

Favorite Color

Blue

Green

Red

Orange

Purple

Favorite Color

Blue 10

Green 5

Red 2

Orange 4

Purple 4

Plans for Vacation

0

2

4

6

8

10

12

Visit family No plans Travel

Type of Plans

Nu

mb

er o

f 7t

h G

rad

ers

Plans for Vacation

Visit family 10

No plans 6

Travel 8

5. The graph shows the 7th graders’ vacation plans. It is representative of the entire school. If there are 300 kids in the school, how many have no vacation plans?

A. 50 students B. 75 studentsC. 100 students D.125 students

Times in 50 Meter Dash

012345678

5.0-5.4 5.5-6.0 6.1-6.4 6.5-7.4 7.5-7.6 7.7-8.5

Times

Nu

mb

er

50 Meter Dash

5.0-5.4 2

5.5-6.0 1

6.1-6.4 3

6.5-7.4 7

7.5-7.6 3

7.7-8.5 4

6. What is the error in this histogram?

7. Is one of these graphs better than the other? Why?

Computers in Stock

05

101520253035

Brand

Num

ber

Computers in Stock

Dell

Compac

MacIntosh

Hewlett Packard

Gateway

Computers in Stock

Dell 31

Compac 20

MacIntosh 29

Hewlett Packard 18

Gateway 12

8. What is the trend of this graph? Can you predict enrollment in 2010?

Student Enrollment

0

200

400

600

800

1000

1990 1995 2000 2005 2010 2015

Year

Nu

mb

er o

f S

tud

ents

Student Enrollment

1995 380

1996 400

1997 400

1998 450

1999 480

2000 540

2001 610

2002 700

2003 720

2004 800

2005 815

2006 830

2007 850

2008 860

9. These box and whisker plots show the death rate and compares years a person has smoked. What does it show you? Could there be any problems with the data?

Test Scores Out Of 100

Stem Leaf

9 2 2 6 8

7 2 4 6 6 8 8 9

6 1 4 4 7 8

5 0 0 2 8 8

Test Scores Out Of 100

Stem Leaf

9 2 2 6 8

7 2 4 6 6 8 8 9

6 1 4 4 7 8

5 0 0 2 8 8

10. This stem and leaf plot has an error. What is it and why is it an error?

9|2 means 92