It is stated that Cueball is doubting, due to his newly found sceptism, which I believe is incorrect.
By stating that "the class helped", Megan is inferring there is a causal relation between Cueball taking a statistics class and him no longer believing correlation implies causation. However, Cueball is replying "well maybe" to indicate there is only a correlation between them, showing he correctly understood the distinction. 18.104.22.168 15:29, 13 May 2014 (UTC)
Another interpretation that explains why the comic is funny is as follows. Cueball replies "well maybe" because he has learned not to infer causation from correlation. But it is also clear that the statistics class caused him to think this way. This pokes fun at a tendency to apply the principle that correlation does not imply causation even when there is direct evidence for causation. 22.214.171.124