notes on how to draw bar graphs and histograms
DESCRIPTION
Subject: mathematics Topic: statistics Simple steps on how to make bar and histogramsTRANSCRIPT
Bar Graphs and Histograms
What do you know about
bar graph? double bar graph? Histogram?
Bar Graph
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English
Hindi
Mandarin
Spanish
A bar graph can be used to display and compare data
The scale should include all the data values and be easily divided into equal intervals.
How to interpret a Bar Graph?
How many of Mr. Snowden’s students are band members?
How many of Mr. Snowden’s students are not band members? 0
12
34
56
7
Femaleband
Female notband
Male band Male notband
The bar graph shows Mr. Snowden’s The bar graph shows Mr. Snowden’s students by gender and band students by gender and band
membershipmembership..
Double Bar Graph
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40
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60
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90
1stQtr
2ndQtr
3rdQtr
4thQtr
Can be used to compare two related sets of data
How to make a Double-Bar Graph?
Choose a scale and interval for the vertical axis.
Draw a pair of bars for each country’s data. Use different colors to show males and females.
Label the axes and give the graph a title. Make a key to show what each bar
represents.
The table shows the highway speed limits on interstate roads .within three states
StateStateUrbanUrbanRuralRural
FloridaFlorida65mi/h65mi/h70 mi/h70 mi/h
TexasTexas70 mi/h70 mi/h70 mi/h70 mi/h
VermontVermont55mi/h55mi/h65 mi/h65 mi/h
Step 1 Choose a scale
and interval for the vertical axis.
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60
80
StateStateUrbanUrbanRuralRural
FloridaFlorida65mi/h65mi/h70 mi/h70 mi/h
TexasTexas70 mi/h70 mi/h70 mi/h70 mi/h
VermontVermont55mi/h55mi/h65 mi/h65 mi/h
Step 2 Draw a pair of bars for each
state’s data. Use different colors to show urban and rural.
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20
40
60
80
Florida Texas Vermont
StateStateUrbanUrbanRuralRuralFloridaFlorida65mi/h65mi/h70 mi/h70 mi/h
TexasTexas70 mi/h70 mi/h70 mi/h70 mi/h
VermontVermont55mi/h55mi/h65 mi/h65 mi/h
Step 3 and 4
Label the axes and give the graph a title.
Make a key to show what each bar represents
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60
80
Florida Texas Vermont
Spe
ed L
imit
(mi/h
)
Urban
Rural
Speed Limit on Interstate Roads
Histogram
Histogram is a bar graph that shows the frequency of data within equal intervals.
There is no space in between the bars.
How to make a histogram?
The table below shows the number of hours students watch TV in one week
Make a histogram of all the data.
Number of hours of TVNumber of hours of TV
11IIII66IIIIII
22IIIIIIII77IIII - IIIIIIII - IIII
33IIII - IIIIIIII - IIII88IIIIII
44 IIII - IIIII - I99IIIIIIII
55 IIII - IIIIIII - III
Step 1 Make a frequency
table of the data. Be sure to use equal intervals
Number of hours of TVNumber of hours of TV
11IIII66IIIIII
22IIIIIIII77IIII - IIIIIIII - IIII
33IIII - IIIIIIII - IIII88IIIIII
44 IIII - IIIII - I99IIIIIIII
55 IIII - IIIIIII - III
Number of Number of hours of TVhours of TV
FrequencyFrequency
1-31-31515
4-64-61717
7-97-91616
Step 2
Number of Number of hours of TVhours of TV
FrequencyFrequency
1-31-31515
4-64-61717
7-97-91616
Choose an appropriate scale and interval for the vertical axis. The greatest value on the scale should be at least as great as the greatest frequency.
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1-3 4-6 7-9
Step 3 Draw a bar for each interval.
The height of the bar is the frequency for that interval. Bars must touch but not overlap.
Label the axes and give the graph title
Hours of Television Watched
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8
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1-3 4-6 7-9Hours
Nu
mb
er
of
stu
de
nts
Number of Number of hours of TVhours of TV
FrequencyFrequency
1-31-31515
4-64-61717
7-97-91616
Hours of Television Watched
0
4
8
12
16
20
1-3 4-6 7-9
Hours
Nu
mb
er
of
stu
de
nts
Can you now make a bar graph, double bar Graph
and a histogram?
The list below shows the results of a typing test in words per minute. Make a histogram of the data.
62, 55, 68, 47, 50, 41, 62, 39, 54, 70, 56, 70, 56, 47, 71, 55, 60, 42
The end