Chia C Chong wrote:
> 
> I have 2 random variables (X and Y). The covariance,c was found equal to
> 20.2006 and their correlation coefficient,p was 0.0245.
> 
> From the statistical book, if their c=0, means that X and Y are uncorrelated
> i.e p=0. However, in my case, c is quite large but p is extremely
> small...So, what justification could I said with this kind of data??
> 
It measn the variances are large.  If s_A is the standard deviation of
A, then 

p_XY = c_XY/(s_X*s_Y)

So for your data, s_X*s_Y = 824.5.  This is why we use p, it's re-scaled
so that the variances are 1, so we can compare correlations of variables
with different variances.  In this case, p looks very close to 0.

Bob

-- 
Bob O'Hara
Metapopulation Research Group
Division of Population Biology
Department of Ecology and Systematics
PO Box 17 (Arkadiankatu 7)
FIN-00014 University of Helsinki
Finland

tel: +358 9 191 28779      mobile: +358 50 599 0540
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meaning
- Beachcomber


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