Line Plots and
Histograms
Similar but Different
Line Plots
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Easy and visual way to organize
data.
consists of a horizontal number line,
each value marked by an x over the
corresponding value on the number
line.
The number of x's above each
number indicates how many times
each number occurred.
Watch! Don’t write yet!
Data Set
58, 30, 37, 36, 34, 49, 35, 40, 47, 47, 39, 54, 47, 48, 54, 50,
35, 40, 38, 47, 48, 34, 40, 46, 49, 47, 35, 48, 47, 46
First put them in numerical order.
30, 34, 34, 35, 35, 35, 36, 37, 38, 39, 40, 40, 40, 46, 46, 47,
47, 47, 47, 47, 47, 48, 48, 48, 49, 49, 50, 54, 54, 58
Now create your graph.
•Find the range of the Data and decide what
increments would best show the data.
•It would be silly to make a graph in
increments of one.
•It would be unnecessary to make the graph
go to 100.
30
35
40
45
50
55
60
Add the Data
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Place an X over the number as it
appears in your data set
30, 34, 34, 35, 35, 35, 36, 37, 38, 39,
40, 40, 40, 46, 46, 47, 47, 47, 47, 47,
47, 48, 48, 48, 49, 49, 50, 54, 54, 58
So What?
The Line Plot allows us to see
some trends more clearly.
 Outliers - data points whose values
are significantly larger or smaller
than other values.
 Clusters - isolated groups of points
 Gaps - large spaces between points
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Which are Outliers?
30 and 58
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Which are Clusters?
34-35 and 46-50
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Where are Gaps?
Between 40 and 46
Between 50 and 54
Try it !
Data Set
30,36, 74, 36, 77, 80 36, 45, 36,
36, 37, 38, 38, 50, 38, 39, 42,
42, 45, 45, 45, 45, 45, 48, 36,
50, 50, 51,52, 38, 52, 74, 77,
Put in Numerical Order
30,36, 36, 36, 36, 36, 36, 37,
38,38, 38, 38, 39, 42, 42, 45,
45, 45, 45, 45, 45, 48, 50, 50,
50, 51,52, 52, 74, 74, 77, 77,80
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Make a Number Line and Plot
30,36, 36, 36, 36, 36, 36, 37, 38,38, 38, 38, 39, 42,
42, 45, 45, 45, 45, 45, 45, 48, 50, 50, 50, 51,52, 52,
74, 74, 77, 77,80
30
35
40
45
50
55
60
65
70
Fill in the x’s in your notes. It’s too hard to do it in a
PowerPoint!
75
80
Histogram
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FREQUENCY is the key
Measure Frequency of data
Like a bar graph but measures the
number of times the data occurs.
Think of a Connect Four game.
Every time a number is in the data,
you drop a checker in the game.
Bar Graph or Histogram?
This is a histogram
of how many
employees make a
certain amount of
money. Every time
there is another
employee in a
salary category, the
histogram gets
taller.
Bar Graphs
The y axis is
showing
Dollars not
Frequency.
This is not a
histogram.
Bar Graph or Histogram
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We want to compare total revenues of five
different companies.
Bar graph. Key question: What is the
revenue for each company?
Bar Graph or Histogram
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We have measured revenues of several
companies. We want to compare numbers of
companies that make from 0 to 10,000; from
10,000 to 20,000; from 20,000 to 30,000 and
so on.
Histogram. Key question: How
many companies are there in each
class of revenues?
Try One
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Data for the age of kids going on the
merry-go-round.
2,3,10,5,3,7,9,4,4,10,6,3,4,8,10,