Lesson 1-7 Pages 40-44

Scatter Plots

What you will learn!1. How to construct scatter plots.

2. How to interpret scatter plots.

Scatter plotScatter plot

What you really need to know!

A scatter plot is a graph that shows the relationship between two sets of data. In a scatter plot two sets of data are graphed as ordered pairs on a coordinate system. A scatter plot may show a pattern or relationship of the data. The relation may be positive or negative, or there may be no relationship.

Example 1:

The table shows the average cost of a loaf of bread from 1920 – 2000. Make a scatter plot of the data.

YearYear 19201920 19301930 19401940 19501950 19601960

CentsCents 1212 99 88 1414 2020

YearYear 19701970 19801980 19901990 20002000

CentsCents 2424 5252 7272 9999

0

10

20

30

40

60

50

70

80

90

01920

1930

1940

1950

1960

1970

1980

1990

2000 Y

ear

Cen

ts

YearYear 19201920 19301930 19401940 19501950 19601960

CentsCents 1212 99 88 1414 2020

YearYear 19701970 19801980 19901990 20002000

CentsCents 2424 5252 7272 9999

Example 2:

Determine whether a scatter plot of the data for the following might show a positive, negative, or no relationship.

Explain you answer.

Height of basketball player and number of rebounds.

2

4

6

8

10

66 68 70 72 74

Reb

ound

s

Height (in)

As the height increases, the rebounds increase. Positive relationship.

Shoe size and math test scores.

60

70

80

90

100

4 6 8 10 12

Tes

t Sco

res

Shoe Size

No Relationship!

Example 3:

The table shows temperatures in degrees Celsius and the corresponding temperatures in Fahrenheit.

Make a scatter plot of the data.

°F°F 3232 4141 5050 5959 6868 7777 8686°C°C 00 55 1010 1515 2020 2525 3030

0

30

40

50

60

7080

90

5 10 15 20 25 30 35 40

Fah

renh

eit

Celsius°F°F 3232 4141 5050 5959 6868 7777 8686

°C°C 00 55 1010 1515 2020 2525 3030

Does the scatter plot show a relationship between °C and °F?

Yes. A positive relationship.

Predict the Fahrenheit temperature for 35°C.

0

30

40

50

60

7080

90

5 10 15 20 25 30 35 40

Fah

renh

eit

Celsius°F°F 3232 4141 5050 5959 6868 7777 8686

°C°C 00 55 1010 1515 2020 2525 3030

95°F

Page 42

Guided Practice

#’s 3-7Link to Pre-Made Lesson

Pages 40-42 with someone at home

and study examples!

Read:

Homework: Pages 42-44

#’s 8-19 all

#’s 23-37

Lesson Check 1-CH1

Page

726

Lesson 1-7

Lesson Check 1-CH1

Study Guide and Review

Pages

47-50

#’s 1-36(Odd answers in back of book)

Prepare for Test!

Page

51

#’s 1-25 Lesson Check1-CH1

Prepare for Test!

Pages

52-53

#’s 1-16