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  1. #1
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    Explanation of QUARTILE calculation (XP)

    Can someone please direct me to a concise (and understandable explanation) of how the QUARTILE function calculates the 1st and 3rd quartiles when there are very few data points (eg 8 or so)? It's pretty straightforward when there is lots of data, but when there are few data points, it's not as clear.

    Thanks!

    Larry

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    Re: Explanation of QUARTILE calculation (XP)

    If you have 8 data points, Quartile 1 lies between point 2 and 3, at a distance of 3/4 of point 2 relative to point 3. So the function takes the second value and adds 0.75 times the difference with the third value. Same for the second: the median. Since there is no center value, it takes the fourth value and adds half of the difference with the fifth. Same goes for the 3rd quartile: it takes the 6th value and adds 0.25 times the difference with the seventh value.

    So the numbers 1,2,3,4,5,6,7,8 yield 2.75, 4.5 and 6.25 respectively

    whereas

    2,4,6,8,10 yield 5.5, 9 and 12.5
    Jan Karel Pieterse
    Microsoft Excel MVP, WMVP
    www.jkp-ads.com
    Professional Office Developers Association

  3. #3
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    Re: Explanation of QUARTILE calculation (XP)

    Jan Karol,

    Wonderful explanation - thanks!!!!!!!!!!!!!!!!!!!!!!!

    Larry

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