
Probability and Statistics Basic Probability and Statistics Math Forum 
 LinkBack  Thread Tools  Display Modes 
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: 623 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.


Tags 
data, grouped, median 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Finding the Median with Categorical Data  varuchi13  Advanced Statistics  2  March 30th, 2014 08:27 AM 
Rolling 3 months YOY data to Monthly YOY data  lumpa  Real Analysis  0  October 19th, 2012 09:07 AM 
Removing correlation from summary (grouped) data  Alonso_Canada  Advanced Statistics  3  March 29th, 2012 02:39 AM 
Finding A Data Set Using Mode and Median  corwin43  Elementary Math  1  October 6th, 2009 05:18 PM 
How to regress actual data towards projected data.  BigLRIP  Advanced Statistics  1  May 18th, 2009 11:01 AM 