In The Idiot Brain: A Neuroscientist Explains What Your Head is Really Up To, Dean Burnett wrote
The correlation between height and intelligence is usually cited as being about $0.2$, meaning height and intelligence seem to be associated in only $1$ in $5$ people.
To me, this sound wrong: I understand the correlation more like the (lack of) error we get when we try to predict one measure (here intelligence) if the only thing we know about that person is the other measure (here height). If the correlation is $1$ or $-1$, then we don't make any error in our prediction, if the correlation is $0.8$, then there is more error. Thus the correlation would apply to anyone one, not just $1$ in $5$ people.
I have looked at this question but I am not good enough in maths to understand the answer. This answer which talks about the strength of the linear relationship seems in line which my understanding but I am not sure.