LineGraphs

Bar Graph vs Line Graph

What is the difference between a bar graph

and a line graph?

Line Graph

A line graph is a graph used to show change over time!!

What can time be measured in???Seconds - Minutes - Hours – Days - Weeks - Months – Years - Decades -

Centuries - etc.

When to use a line graph? Would we use a line graph

in the following situations:•To show how many people like pizza in this class? NO

•To show how many people live in East Meadow? NO

•To show how much it rained each month this year? YES- because months and years deal with time.

Birthdays?

Our birthday does deal with time doesn’t it? (months/years)

But, our birthday is constant, meaning it never changes.

A line graph shows change in time, so we would not use it for this type of graph.

                                                      

Would we use a line graph to show when our birthdays are?

How do we make a line graph?

A line graph ALWAYS has a title!

A line graph has two different axis’s

An axis is either the horizontal line (called x) or the vertical line (called y) that form the base lines of a graph.

Y

X

                     

X-axis and Y-axis When you are making a line graph, the

x-axis is always horizontal, and the y-axis is always vertical.

The x and y-axis usually starts with zero on a line graph

It is important to make sure that the intervals on our y-axis are always equal.

What do I mean by this?

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Plotting a Line graph When we are plotting a line graph, it is

important to read what information is on each axis.

There must be a label on each axis that describes the information.

Much like a bar graph, we look at the x-axis first in order to plot our points.

Time in minutes

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Is this an acceptable graph?

Time

Car Trip

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What information do you need to interpret a graph?

•The graph we just looked at does not have any numbers on the x-axis or the y-axis.

•Can we still draw conclusions and answer questions about that graph?

•How many times did the driver stop driving during the trip?Time

Car Trip

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Miles traveled during the week

0

10

20

30

40

50

60

70

Mon. Tues. Wed. Thurs. Fri. Sat. Sun.

Days

Mile

s T

rav

ele

d

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Q & AHow many days did this person travel less than 30 miles?

Which day did the driver travel the least amount of miles?

Why might someone want to keep track of their miles for the week?

5 days

Sunday

To figure out how much gas they need a week.

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U.S. Corn in Acres

55

60

65

70

75

80

85

Years

Acr

es o

f co

rn (

in m

illi

on

s)

Q & A About how much corn did the U.S. have in 1991?

What does the y-axis represent in the graph?

Can you think of another title for this graph?

About 77 million acres

The rise and fall of corn in the U.S.

Acres of corn in millions.

Double Line Graphs

Are line graphs that display two sets of data at the same time. Usually they are related in some way.

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Example1

Year Hourly Rate

1970 1.60

1980 3.10

1990 3.80

2000 5.15

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U.S. Minimum Wage

Example2

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Number of pounds for Sara’s two pets

Jan Feb Mar Apr May Jun

Ginger 3 9 15 21 24 25

Toto 4 8 13 17 24 26

Assignment

Page 316 problems 1-10

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Make your own….. •Now that you have had time to interpret graphs, I would like you to make your own graphs.

•Remember to read the information carefully and label everything!

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Amount of Rain From Yesterday's Storm

0

2

4

6

8

10

12

14

1PM 2PM 3PM 4PM 5PM 6PM 7PM

Time in Hours

Am

ou

nt

in M

illi

lete

rs

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Calories burned while running

0

20

40

60

80

100

120

140

160

180

200

220

240

Hours

Calo

ries

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Value of TY beanie baby "Slowpoke Sloth"

0

5

10

15

20

25

30

1996 1997 1998 1999 2000 2001

Year

Va

lue

in D

olla

rs

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Do these have the same information on them?

Test grades

0

50

100

1 2 3 4 5 6

Week

So

urc

e

Test grades

7075

8085

90

1 2 3 4 5 6

Week

So

urc

e

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Great Job!