correlation function

  • Thread starter Thread starter leopons_rock
  • Start date Start date
leopons_rock -

Excel's Help shows the formulas for each function.

CORREL uses n, COVAR uses n, and STDEV uses n-1, where n is the sample size.

CORREL(x,y) does equal COVAR(x,y)/(STDEVP(x)*STDEVP(y)).

- Mike Middleton
http://www.DecisionToolworks.com
Decision Analysis Add-ins for Excel
 
Hi. A math program showed Covar using a poplulation size.( ie n-1, not n)
In other words, if the size is 4, then it divided by 3.
So, with n=4 data points, try muliplying by n/(n-1)
Make sure you use ( ) around the denominator also.
(Not always perfect, but I trust math programs much more than Excel.)

=CORREL(y,x)=COVAR(x,y)/(STDEV(x)*STDEV(y))*4/3

-> TRUE

HTH
Dana DeLouis
 
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