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Thread "box plot ranges" Started by Paul Edmunds on: 03/29/2008 10:30pm
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box plot ranges
Posted by: Paul Edmunds  on: 03/29/2008 10:30pm
Hi Vandan,
I have been making box plots and using the data labels of 25%, 50%, and 75%. I am wondering what percentage of the data is typically demonstrated above the minimum and maximum whiskers? That is, in what range do the outliers belong to?
Thank you!
Paul
Re: box plot ranges
Posted by: Vandan  on: 12/11/2006 9:17am
Paul:

VTools uses following to calculate whiskers:

* Upper Whisker: = Min (Max(data), 75% + (1.5 * IQR))
* Lower Whisker: = Max (Min(data), 25% - (1.5 * IQR))

IQR := InterQuartile Range (75% - 25%)

i.e. anything higher than 75th percentile + 1.5 IQR is an outlier.

For a well behaved data set, there should be no outliers!
Re: box plot ranges
Posted by: Paul Edmunds  on: 02/13/2007 4:32pm
Hi Vandan - hope you are off to a great new year 2007!

Following up on some help you offered me in December, am I correct in saying that values below the minimum whisker would be: the 25th percetile - 1.5 IQR? I am trying to document how outliers above and below the max and min are calculated.

Thank you!
Paul



VTools uses following to calculate whiskers:

* Upper Whisker: = Min (Max(data), 75% + (1.5 * IQR))
* Lower Whisker: = Max (Min(data), 25% - (1.5 * IQR))

IQR := InterQuartile Range (75% - 25%)

i.e. anything higher than 75th percentile + 1.5 IQR is an outlier.

For a well behaved data set, there should be no outliers!
Re: box plot ranges
Posted by: Vandan  on: 02/14/2007 6:55pm
That is correct.
Re: box plot ranges
Posted by: Paul Edmunds  on: 02/16/2007 1:28am
Thank you, Vandan!
Paul
Re: box plot ranges
Posted by: test  on: 04/17/2008 12:37pm
test
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