Question

The coefficient of correlation is under- root of two .................

Answer 1

Answer:

A squared number is always POSITIVE.

But if you take the square root of the number - you can get either the negative or the positive square root.

Correlation is the (Absolute) value of the square root - which means you take the positive square root only.

The sign of the correlation gives you whether the two variables you are looking at are positively, negatively or not correlated. (+, -, 0 being the sign of the correlation).