# Thread: what could be the meaning of last term in the correlation equation?

1. ## what could be the meaning of last term in the correlation equation?

E= sqrt(<x^2><y^2>-(<x*y>)^2).
In this equation what exactly <x*y>^2 represents? pls help

2. ## Re: what could be the meaning of last term in the correlation equation?

Originally Posted by Ranjini
E= sqrt(<x^2><y^2>-(<x*y>)^2).
In this equation what exactly <x*y>^2 represents? pls help
What you have written is not the equation for the product-moment coefficient of correlation. And, why do you use the
notation "< >"?

3. ## Re: what could be the meaning of last term in the correlation equation?

The notation < > usually mean inner product of a Hilbert space, which can be defined as the covariance between two random variables. However it has two arguments :P

4. ## Re: what could be the meaning of last term in the correlation equation?

A think a more commonly used notation (for the product moment correlation) is :

where the numerator is the dot product.

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