Statistics and Facts: Any Correlation?

All right, this is indeed a hilarious post from Greg Mankiw. The statistics show that children from higher income families are getting higher average SAT scores, and some people claim that there is a correlation between income and better result of tests. However, Mr. Mankiw theorizes that the correlation is not on the income rate, but on the fact that smart people are making more money and these people pass their genes to their children, thus smart children comes from smart parents not from rich parents. Okay, I'm not a professional statistician, but when dealing with statistics, I always remember what David Hume, a Scottish philosopher, has taught us on making a conclusion from our experience: just because in your experience an act is always followed by the second act does not mean that there is a causality between the first act and second act. In Nassim Nicholas Taleb's wisdom (taken from his book "Fooled by Randomness"): " no amounts of observations of whit