Rahat Bokhari wrote:
>
> Hi.
> In a study a data like below is available for variable X and Y
> that depend upon independent variable Z.
>
> Sapmle N= 96 Mean= 3.2 Std.dev= 0.7 is given for dependent variable
> X Sample N= 59 Mean= 1.88 Std.Dev= 1.9 for dependent
> variable Y
> Is there any way to find the relationship between X and Y.
> Regards
> Bokhari
These informations are related to variables X and Y separately.
For the linear association between Y and X you need a covariance
Cov(X,Y) (or correlation) information as measure of association
between X and Y.
In this case the coefficients of regression Y=a*X + b (+E) can be
obtained simply by the formula:
a = Cxy/Vx and b = My - a*Mx.
Where Mx=moy(X); My=Moy(Y); Vx=Variance(X) and Cxy=Covariance(X,Y)
Note that the variance of Y is not used and it's normal, because the
main of the regression is to explain the variability in Y by X.
Hassane.
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