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Grouped Frequency Table Median?

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1. Hey guys,

Just wanted to ask a quick question, How do you work out the median of a Grouped frequency table? I heard you use formula which is n+1/2 and what is n?.....Also one you have found out the answer how do you know which group it's in?
2. n I think is your total frequency then once you've found the group its in I'm pretty sure you interpolate
equation b-((n/2)-f)/(fm)xw
where b is lower class bound
f is sum of frequencies below class
fm is frequency of median class
w is class width
3. (Original post by Nelo Angelo)
n I think is your total frequency then once you've found the group its in I'm pretty sure you interpolate
equation b-((n/2)-f)/(fm)xw
where b is lower class bound
f is sum of frequencies below class
fm is frequency of median class
w is class width
Thanks but i'm not talking about upper bounds and lower bounds, and i'm not talking about histograms
4. So nobody knows on TSR how to find out the median on a grouped frequency table?
5. one of the guys above said it - you interpolate.

If its grouped then you're assuming the data is continuous so you have to interpolate;

m + cw[(0.5n-fc)/f]

where m = minimum boundary of median class
cw = class width of median class
n = total number in the sample
fc = cumulative frequency of the classes below the class
f = frequency of the median class
6. 1-n+1/2=position of the median
n=number of values or the sample size
2-you then need to add a cumlative frequency column to the table and the number you got for 1- needs to be fitted in. The group it is in is the median group, but i'm not sure how you work out the actual value.

for example-
weight frequency cumlative frequency
1<n<2 4 4
2<n<3 10 14

n+1/2=14+1/2=7.5th number
7.5 is larger than 4, but less than 14, so is in the 2<n<3 group
2<n<3 is the median group.

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