Shee needs to read 'Freakonomics' by Stephen J Levitt.
In it you will learn how statistics do now necessarily show cause and effect.
Have you seen the comercial where a Hollywood actor says 'studies show, kids who have more books in their homes, do better in school'. So they want you to donate books to poor kids.
Well - donating books to kids is a great idea - but it wont magically help them in school.
The statistic that kids with more books at home tend to do better is true - but the BOOKS are not the cause of the kids doing better. The books are more of a gauge of the household. Households with more books tend to have parents who are better educated and more affluent (thus can buy more books). And they tend to have two parent families. So the reason kids with more books tend to do better is:
They come from better genetic stock
They have enough food and good food for healthy brain development.
They have two parents to help raise and teach them.
So the books have NOTHING to do with how well kids do in school.