6 jun. 2011
Suppose you tested a classroom of 30 kids for about 40 separate variables. Chances are you would find that some of those variables would line up by sheer chance. In other words, you could find a strong correlation between two independent variables. If you came up with even more variables you could find even stronger correlations. Four of the five kids who wore glasses also had names beginning with J. This is a little like shooting bullets at a barn and then going and drawing targets around the bullet holes, the Texas Marksman's Fallacy. Correlation is not causation, but sometimes correlation is not even correlation.