Bar Graph

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

STUDENTS PER CLASS
30
15
Number of Students
0
7
8
6
Grade
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• 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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• Since a bar graph uses rectangular bars then with
  a quick glance, you can see
• How data items compare to each other
• The least and greatest data items

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

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A histogram is also used to compare data clearly
and efficiently.
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This histogram groups the data into ranges or
intervals.
What is the interval?
Letter Grades A 90-100 B 80-89 So forth
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Pictograph
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• A pictograph uses pictures or symbols to compare
  data.

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A pictograph has a key that tells the value of
each picture.
KEY
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• A pictograph is similar to the bar graph and
  histogram because it is also used best to compare
  data.

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

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

Average Studying Time
Each group of data will have its own line.
3hrs
6th
2hrs
7th
1hrs
0
1990
1995
2000
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• 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.
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• A steady trend may be used to help predict what
  will likely happen in the future.

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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?
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C. Did CD prices increase or decrease from 1999
through 2002?
Increase
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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?
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C. Did CD prices increase or decrease from 2001
to 2002?
Increase
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Line Plot
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• A line plot uses a horizontal line and individual
  data points (usually Xs) to show how the data
  groups or clusters.

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

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• A line plot is best used when grouping data
  together.

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

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Number of Pets in each Household
Outliers, or data items that are much larger or
smaller than the rest of the items are easy to
spot as well.
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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 data-a line graph or bar
graph? Draw the more appropriate graph.
Neighbor Sal Jax Pete Lar Ni
Feet 32 11 5 25 20
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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.
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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
data-a line plot or line graph?
Student Chad Julz Shane Lyn Rex
Tickets 4 7 4 4 5
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Check It Out Example 1B Continued
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.
xxx
x
x