Bar Graphs and Bar Graphs and HistogramsHistograms

What do you know aboutWhat do you know about

bar graph?bar graph? double bar graph?double bar graph? Histogram?Histogram?

Bar GraphBar Graph

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A bar graph can A bar graph can be used to be used to display and display and compare datacompare data

The scale The scale should include should include all the data all the data values and be values and be easily divided easily divided into equal into equal intervals.intervals.

How to interpret a Bar GraphHow to interpret a Bar Graph??

How many of Mr. How many of Mr. Snowden’s Snowden’s students are students are band members?band members?

How many of Mr. How many of Mr. Snowden’s Snowden’s students are not students are not band members?band members? 0

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34

56

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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 GraphDouble Bar Graph

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2ndQtr

3rdQtr

4thQtr

Can be used to Can be used to compare two compare two related sets of related sets of datadata

How to make a Double-Bar How to make a Double-Bar GraphGraph??

Choose a scale and interval Choose a scale and interval for the vertical axis.for the vertical axis.

Draw a pair of bars for each Draw a pair of bars for each country’s data. Use different country’s data. Use different colors to show males and colors to show males and females.females.

Label the axes and give the Label the axes and give the graph a titlegraph a title..

Make a key to show what Make a key to show what each bar represents.each bar represents.

The table shows the highway The table shows the highway speed limits on interstate speed limits on interstate roads roads . .within three stateswithin 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 1Step 1

Choose a scale Choose a scale and interval for the and interval for the vertical axis.vertical axis.

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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 2Step 2 Draw a pair of bars for each Draw a pair of bars for each

state’s data. Use different state’s data. Use different colors to show urban and rural.colors to show urban and rural.

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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 4Step 3 and 4

Label the axes and Label the axes and give the graph a give the graph a title.title.

Make a key to Make a key to show what each show what each bar representsbar represents

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Florida Texas Vermont

Spe

ed L

imit

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Speed Limit on Interstate Roads

HistogramHistogram

Histogram is a bar graph that Histogram is a bar graph that shows the frequency of data shows the frequency of data within equal intervals.within equal intervals.

There is no space in between There is no space in between the bars. the bars.

How to make a histogramHow to make a histogram??

The table below shows the number of The table below shows the number of hours students watch TV in one week hours students watch TV in one week

Make a histogram of all the dataMake 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 1Step 1 Make a frequency Make a frequency

table of the data. table of the data. Be sure to use Be sure to use equal intervalsequal 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 2Step 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 Choose an appropriate scale and interval for the vertical axis. The greatest value on the scale should be at least as axis. The greatest value on the scale should be at least as great as the greatest frequency.great as the greatest frequency.

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Step 3Step 3 Draw a bar for each interval. Draw a bar for each interval.

The height of the bar is the The height of the bar is the frequency for that interval. frequency for that interval. Bars must touch but not Bars must touch but not overlap.overlap.

Label the axes and give the Label the axes and give the graph titlegraph title

Hours of Television Watched

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Number of Number of hours of TVhours of TV

FrequencyFrequency

1-31-31515

4-64-61717

7-97-91616

Hours of Television Watched

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Can you now make a bar Can you now make a bar graph, double bar Graph graph, double bar Graph

and a histogramand a histogram??

The list below shows the results of The list below shows the results of a typing test in words per a typing test in words per minute. Make a histogram of the minute. Make a histogram of the data.data.

62, 55, 68, 47, 50, 41, 62, 39, 54, 62, 55, 68, 47, 50, 41, 62, 39, 54, 70, 56, 70, 56, 47, 71, 55, 60, 4270, 56, 70, 56, 47, 71, 55, 60, 42

The endThe end