Join TSR now and get all your revision questions answeredSign up now

Grouped Frequency Table Median? Watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    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?
    Offline

    0
    ReputationRep:
    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
    • Thread Starter
    Offline

    0
    ReputationRep:
    (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:confused:
    • Thread Starter
    Offline

    0
    ReputationRep:
    So nobody knows on TSR how to find out the median on a grouped frequency table?
    Offline

    1
    ReputationRep:
    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
    Offline

    0
    ReputationRep:
    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.
 
 
 
Poll
Is GoT overrated?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.