Math Is Fun Forum

Ansh Agrawal

Member

Registered: 2012-01-26

Posts: 11

Rank correlation - please help - just a doubt

I came across this sum :

I have been given the rankings of ten contestants in a beauty contest.. rankings are done by 3 judges.. and their decisional rankings have been given in three columns.. So the rankings have already been given..

They have told this : " Use rank correlation to discuss which pair of judges has the nearest approach to common tastes in beauty

What i did is i paired the 3 judges, so i had 3 pairs.. then i found out the rank correlations for respective pairs.. but m doubtful for the final judgement that we have been asked to make. HOW TO DO THAT ? can anyone help ?

thanks...

Bob

Administrator

Registered: 2010-06-20

Posts: 10,623

Re: Rank correlation - please help - just a doubt

hi Ansh Agrawal

You've done all the hard work here.  Now you just need to interpret the correlation results.

The closer a correlation is to 1, the greater is the agreement between the judges.  So which pair gave the highest value?

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Ansh Agrawal

Member

Registered: 2012-01-26

Posts: 11

Re: Rank correlation - please help - just a doubt

well, the first pair has 0.55, second one has 0.73, and third one has 0.05..

today i had  a test. i got the same in it..n i judged 0.73 as the correct answer.. but is that correct ?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,623

Re: Rank correlation - please help - just a doubt

Yes it is!

Correlation values range from -1 to + 1.

+1 means a perfect correlation.  Two judges would have put exactly the same order.

-1 means a perfect but negative correlation.  Two judges would have made exactly the opposite order from each other.

0 means no correlation.  The two judges gave completely mixed up rankings with no agreement and no 'anti' agreement.

A value of 0.73 means there is a fair amount of agreeement.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Ansh Agrawal

Member

Registered: 2012-01-26

Posts: 11

Re: Rank correlation - please help - just a doubt

well thanks bob ! seriously u made me relieved.. my friend told that 0.55 would be the answer because it states ' common tastes ' ... she told that common implies somewhere near half.. did she have a point ?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,623

Re: Rank correlation - please help - just a doubt

No.  In 'common' with each other!

B

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Ansh Agrawal

Member

Registered: 2012-01-26

Posts: 11

Re: Rank correlation - please help - just a doubt

well thanks finally u helped me n i cud do d sum nicely hey u had answered my area problem.. but i had posted anoder reply.. did u check it ? could you please check it and help me out ? area by definite integrals..