Math Is Fun Forum

samuel

Member

Registered: 2009-06-14

Posts: 2

Correlation formula

I have a problem here.
Previously I have done a correlation work between two sets of data measuring the same parameter (weight), using two measurement equipments, A & B.
Data from both equipment gives two sets of data, set A & set B.
The formula derived as below:
Y=3.69395X-0.30099

There is another correlation work done between measurement equipment A and another equipment, C;
The formula derived as below:
Y=0.952X+0.0291

Now I need to derive another correlation formula between equipment A & C.
Could someone advise if there is any method I could calculate that?

Thanks in advance!!

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Correlation formula

Hi samuel;

There is another correlation work done between measurement equipment A and another equipment, C;
The formula derived as below:
Y=0.952X+0.0291

I don't understand didn't you already do a fit for A and C above?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

samuel

Member

Registered: 2009-06-14

Posts: 2

Re: Correlation formula

Opps.. thanx for pointing out Bobby..
Its a typo actually...
I would like to derive the correlation formula between B & C.
(Not A & C)
However, data for A & B is from one set of samples, while B & C is using another set of samples..
Now the only way I could think of is to let C measure the same set of samples that was used for correlation between A & B,
then derive the formula between A & C base on the new measurement data measured by C.
Just wonder is there any other way?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Correlation formula

Hi samuel;

   Since you already have B from your A and B measurement and C from your A and C measurement it seems that you will have to do another linear fit between B and C. I am drawing a blank on any other way to do it.

Last edited by bobbym (2009-06-15 03:45:43)

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Correlation formula

[moved to "Help Me"]

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman