# Math Help - Correlation

1. ## Correlation

I have this question... I've been given the answer but I'm not sure why that's the answer. So I have this regression equation that is
Y
= 20.3 5.4X. The questions asks what the correlation between the two is (an answer is not expected) and I know that it's negative and close to -0.1. I know that the correlation is negative because the slope (b) is negative but how do you know that the correlation is strong, moderate or weak? Like how can you tell just from looking at the equation?

Anna

2. Originally Posted by princess_anna57
I have this question... I've been given the answer but I'm not sure why that's the answer. So I have this regression equation that is
Y = 20.3 5.4X. The questions asks what the correlation between the two is (an answer is not expected) and I know that it's negative and close to -0.1. I know that the correlation is negative because the slope (b) is negative but how do you know that the correlation is strong, moderate or weak? Like how can you tell just from looking at the equation?

Anna
If the least squares regression line is $y = a + bx$ then $b = r \frac{s_x}{s_y} \Rightarrow r = \frac{s_y}{s_x} b$.

So you can't get the value of $r$ simply by looking at the least squares regression line.