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December 1st, 2018, 09:16 AM  #1  
Newbie Joined: Jun 2011 Posts: 17 Thanks: 0  Median for grouped data
Hi, I was studying a topic related to statistics and came across Median for Grouped data Formula for finding it is pretty simple. where Lm is the lower limit of the median class, n is the total number of observations, Fmâˆ’1 is the cumulative frequency of the class preceding the median class, fm is the frequency of the median class, c is the class width. But i wanted to know the derivation of this formula and came across https://math.stackexchange.com/quest...rgroupeddata and http://mathforum.org/library/drmath/view/71767.html which i found interesting. I have some difficulty in finding the median of the example give at http://mathforum.org/library/drmath/view/71767.html Quote:
Thanks & Regards, Dev  
December 5th, 2018, 09:50 AM  #2 
Senior Member Joined: Oct 2013 From: New York, USA Posts: 635 Thanks: 85 
The problem is written wrong because multiple of ten are in two groups. For example, if one group ends at 80, the next group should start at >80, not 80. Alternatively, it could say something just above 80 like 80.01. Your division of 10/6 = 5/3 is correct. However, since 80 and 90 are in two groups, if the data points were 80, 81 2/3, 83 1/3, 85, 86 2/3, 88 1/3, and 90, it is impossible to say whether 5, 6, or 7 points go in the 80 to 90 range. I do not think it would be fair to mark any answer wrong because the problem is written wrong.


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data, grouped, median 
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