math-bar chart

8/7/2019 Math-bar chart

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BAR CHARTBAR CHART

JEE MING HOITAN PEI JIN


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What is bar chart??


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A bar chart represents the data ashorizontal or vertical bars. The length ofeach bar is proportional to the amount thatit represents.

There are 3 main types of bar charts. Vertical bar chart Horizontal bar chart

Double bar chart

Bar Charts/Bar GraphsBar Charts/Bar Graphs


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When constructing a bar chart it is

important to choose a suitable scale torepresent the frequency.


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show each data category in a frequencydistribution

display relative numbers or proportions ofmultiple categories

summarize a large data set in visual form clarify trends better than do tables estimate key values at a glance permit a visual check of the accuracy and

reasonableness of calculations be easily understood due to widespread use

in business and the media

AdvantagesAdvantages


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require additional explanation be easily manipulated to yield false

impressions fail to reveal key assumptions, causes,

effects, or patterns

DisavantagesDisavantages


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Watch out for inconsistent scales. If you'recomparing two or more charts, be sure they

use the same scale. If they don't have thesame scale, be aware of the differences andhow they might trick your eye.

Be sure that all your classes are equal. For

example, don't mix weeks and months, yearsand half-years, or newly-invented categorieswith ones that have trails of data behind them.

Be sure that the interval between classes is

consistent. For example, if you want tocompare current data that goes month bymonth to older data that is only available forevery six months, either use current data forevery six months or show the older data with

blanks for the missing months.

Tips:Tips:


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Mean the average height of all the bars. Maximum the maximum value (tallest bar)

in the series. Minimum the minimum value (shortest bar)

in the series. Sample Size the number of values (bars) in

the series.

Range the maximum value minus theminimum value. Standard Deviation Indicates how widely

data is spread around the mean.

For each bar in the bar chart,For each bar in the bar chart,the following statistics arethe following statistics are

useful:useful:


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BARBARGRAPHGRAPH

The

frequencyscale muststart from 0and go up inequal steps

frequenc

y

Label bothof the axes

Bars shouldhave equalwidth

Chart to show year 7 favourite types of music

Type of music


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Example :The following table shows the number of

visitors to a park for the months

January to March.

a) Construct a vertical and a horizontalbar chart for the table.

b) What is the percentage of increase ofvisitors to the park in March compared

to January? c) What percentage of visitors came in

February compared with total numberof visitors over the three months?

Month January February MarchNumber ofvisitors

150 300 250


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b) Increase in March compared to January is

c) Percentage of visitors in Februarycompared to the total number of visitors is


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Thank YouThank You


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Example :The following frequency graph shows

the number of adult visitors and childvisitors to a park. Construct a side byside double bar chart and a stackeddouble bar chart for the frequencytable.

Month April May June

Number ofadultvisitors

300 500 700

Number ofchildvisitors

200 600 600


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Solution:Solution:


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math-bar chart

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