What’s really interesting about correlations is that they measure the amount of distance that one variable covaries in relation to another. So, if both variables are highly variable (have lots of wide-ranging values), the correlation between them is more likely to be high than if not. Now, that’s not to say that lots of variability guarantees a higher correlation, because the scores have to vary in a systematic way. But if the variance is constrained in one variable, then no matter how much the other variable changes, the correlation will be lower. For example, let’s say you are examining the
...more
