kunalkulkarni wrote:there are 2 sets of data:
X = {0,0,0,4,4,4,6,6,8}
Y = {50,38,56,34,32,42,28,34,29}
There is a negative correlation between X and Y.

Can anyone please explain me. how is the above statement true?
My understanding is as follows:
positive correlation - directly proportional
negative correlation - inversely proportional

Please help me with above question.
Thanks in advance,
Kunal

Hi kunal,

Your understanding of negative correlation is perfect. Here, we have two sets, X and Y. These two sets are in negative correlation because, with every increase in the value of element in X, value of element in Y is decreasing.


0 - 50************************
***********0 - 38 ************
************************0 - 56
4 - 34************************
***********4 - 32*************
************************4 - 42
6 - 28************************
***********6 - 34*************
************************8 - 29


I hope this pictorial representation will make it easy for you to comprehend.

Hey Hemant,
Thank you for the reply.
So the main catch is to find the transitioning numbers as X changes from 0 to 6. Just to ensure I understood it correctly, if below was the series for X and Y
0 - 50
0 - 38

4 - 42
4 - 36

6 - 32
6 - 40

then it would be impossible to find negative or positive correlation. right?

Thanks,
Kunal

Hi Kunal,

I did some modification in pictorial representation in my previous post. I guess BTG post skips white space in forum. Hope this make it clear.

Thank you Hemant and Tommy. Appreciate your help.

Cheers,
Kunal

As per my understanding, correlation is a statistical term with a proper formula. Its value varies from -1 to +1 for any set of data, with value of +1 representing perfect linear positive correlation (data set will draw a straight line in cartesian plane), similarly -1 represents a straight line with negative slope.
Basically, for any given set of data, even random, correlation will be either positive or negative, close to zero for highly uncorrelated/random data.
In the above question, it is clear that when X increases, Y decreases, other than for some exceptions, which can be ignored.

This is my understanding, open for other explanations.

Hey Kunal,

Could you please elaborate on this.
I'm not quite sure that I got this

Cheers,
Taz

kunalkulkarni wrote:Hey Hemant,
Thank you for the reply.
So the main catch is to find the transitioning numbers as X changes from 0 to 6. Just to ensure I understood it correctly, if below was the series for X and Y
0 - 50
0 - 38

4 - 42
4 - 36

6 - 32
6 - 40

then it would be impossible to find negative or positive correlation. right?

Thanks,
Kunal