Bar Bar GraphGraph

A single bar graph uses the same color or shade of bar to compare amounts, such as number of students per class.

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STUDENTS PER CLASS

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Grade

A double bar graph uses two or more colors or shades of bars and a key to compare amounts, such as the number of boys and girls in each class.

STUDENTS PER CLASS

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Class Number

GirlsBoys

Since a bar graph uses rectangular bars then with a quick glance, you can see…

1)How data items compare to each other

2)The least and greatest data items

HistogrHistogramam

A histogram is a special kind of bar graph that shows how ranges of ranges of datadata change or differ from one another.

Number of students receiving grades

A histogram is also used to compare data clearly and efficiently.

Number of students receiving grades

This histogram groups the data into ranges or intervals.What is the interval?Letter Grades:

A 90-100

B 80-89

So forth

PictograPictographph

A pictograph uses pictures or symbols to compare data.

A pictograph has a key that tells the value of each picture.

KEY

A pictograph is similar to the bar graph and histogram because it is also used best to compare data.

Line Line GraphGraph

Average Daily Temperature for January 1-7 in Degrees

Fahrenheit

A single line graph uses one line to show how something changes over time.

A multiple line graph compares two or more groups of data during the same time period.

Each group of data will have its own line.

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1990 1995 2000

Average Studying Time

6th

7th

A line graph shows trends, or how things change over time.

By looking at the line(s) on a line graph, you can tell whether something is increasing, decreasing or staying the same.

A steady trend may be used to help predict what will likely happen in the future.

Additional Example 2: Reading a Line Graph

Use the line graph to answer each question.

A. In which year did CDs cost the most?2002

B. About how much did CDs cost in 2000?$15

C. Did CD prices increase or decrease from 1999 through 2002?Increase

Check It Out: Example 2

Use the line graph to answer each question.

A. In which year did CDs cost the least?1999

B. About how much did CDs cost in 1999?$13

C. Did CD prices increase or decrease from 2001 to 2002?Increase

Line Line PlotPlot

A line plot uses a horizontal line and individual data points (usually Xs) to show how the data groups or clusters.

Each X on a line plot stands for one piece of data.

A line plot is best used when grouping data together.

Line plots are a quick way to determine the mode because it is the number on the scale with the most Xs.

Outliers, or data items that are much larger or smaller than the rest of the items are easy to spot as well.

Number of Pets in each Household

Check It Out: Example 1A

A table shows the number of feet of grass each neighbor must mow. Which graph would be more appropriate to show the dataa line graph or bar graph? Draw the more appropriate graph.

Neighbor Sal Jax Pete Lar Ni

Feet 32 11 5 25 20

Check It Out: Example 1A Continued

Think: is the information in the table describing a change over time? Is the information in the table divided into different categories?

The table shows the number of feet each neighbor mows. The data should be displayed in separate categories. So a bar graph is more appropriate than a line graph. 0

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Sal

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Check It Out: Example 1B

The table shows the number of tickets each student purchased for the school carnival. Which graph would be more appropriate to show the dataa line plot or line graph?

Student Chad Julz Shane Lyn Rex

Tickets 4 7 4 4 5

Think: is the information in the table describing the frequency of values? Is it describing a change over time?

A line plot shows the frequency of values on a number line. So a line plot is more appropriate than a line graph.

x

xxx x

1 2 3 4 5 6 7 8 9

Check It Out: Example 1B Continued