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#1 2007-07-18 04:55:28

Daniel123
Member
Registered: 2007-05-23
Posts: 663

Histogram

Hello smile

I'm trying to draw a histogram with the below classes, but I'm not sure where on the x-axis to make the divisions between the classes e.g. should the first block end at 4 or at 5, etc?

      Age            Class width      Frequency      Frequency Density
      0-4                    4                   10                       2.5
     5-14                   9                   32                       3.6   
    15-19                  4                   30                        7.5
    20-34                 14                  270                      19.3
    35-49                 14                  300                      21.4
    50-64                 14                  405                      28.9
    65-74                  9                   338                      37.6     
    75-89                 14                  615                      43.9

Thanks!

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#2 2007-07-18 05:37:39

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: Histogram

Put the divisions at the lower bounds of each class.

Age is a special statistic because it's generally rounded down to the nearest whole number. For example, if a 4-year-old had their birthday tomorrow, they'd still say that they were 4, rather than 4.997 or something.

You also need to add one to each entry in the class width, and change the frequency densities accordingly.


Why did the vector cross the road?
It wanted to be normal.

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#3 2007-07-18 05:40:10

Daniel123
Member
Registered: 2007-05-23
Posts: 663

Re: Histogram

Great, thank you smile

Last edited by Daniel123 (2007-07-18 05:40:23)

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#4 2007-07-18 06:06:17

Daniel123
Member
Registered: 2007-05-23
Posts: 663

Re: Histogram

How would I then place the divisons for this next question?

The weights to the nearest pound of a group of students are summarised below. Draw a histogram to illustrate these data.

Weight     Frequency
25-29           2
30-34           6
35-39          17
40-44          24
45-49          35
50-54          27
55-59          19
60-64          13
65-69           5
70-74           2

Thanks

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