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Student Support Forum: 'BoxWhiskerPlot quartiles issue.' topicStudent Support Forum > General > "BoxWhiskerPlot quartiles issue."

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mike
04/26/07 03:34am

Hi,

I am using BoxWhiskerPlot from Statistics`StatisticsPlots` to create a box-plot for some data. However, the quartiles seem to be incorrect in the graphic returned.

For example,

I create BoxWhiskerPlot for the following 20 values.

l = {40, 42, 44, 44, 45, 50, 51, 52, 53, 56, 56, 59, 59, 60, 69, 73, 77, 78, 83, 84};

n = number of elements in list = 20

Q1 - the lower quartile should be the (n + 1)/4 th value which in this case is 46.25 but appears to be 45 on the plot.

Q2 - the mean is 56 which is correct on the plot.

Q3 - should be 3*(n + 1)/4 th which is 15.75th = 72 but appears to be 69 on the box-plot.

Any ideas?



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Author Date Posted
BoxWhiskerPlot quartiles issue. mike 04/26/07 03:34am
Re: BoxWhiskerPlot quartiles issue. yehuda ben-s... 04/28/07 2:05pm
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