Believe it or not, this Weird Science story is essentially a lecture on the law of large numbers.
A very worried college professor tells his class he's just witnessed the failure of one of the most essential laws of nature: the law of large numbers. He then proceeds to illustrate this law, obviously in a simplified (oversimplified?) version since this is a comic book: if you flip a coin, you can get heads or tails. But if you flip it one hundred times, you'll get fifty heads and fifty tails, or at least similar numbers. If the LLN failed, explains the professor, it could cause catastrophes: if every year Miami is visited by, say, 30,000 tourists, without the LLN it could happen that every citizen of the US decides to go to Miami at once, chaos ensuing form the forming mob.
(Warning: spoiler incoming) We discover that the professor brought the subject up because of the 379 students of the course, with an average 360 attending every day, only one has shown up: an apparent breach of the LLN, says the professor. The only attendant, anyway, tells him not to worry: he reveals he's actually the janitor, and it's Sunday.
Also, after reading your post about Robert M. Coates's "The Law", I tried to understand if what was described in "Off Day!" was actually the law of averages under a false name. I believe that what was explained in the comic was closer to the real law of large numbers, even if it was dumbed down to flip-the-coin examples (it was repeatedly stressed that it takes a large number of events, while according to Wikipedia the law of averages expresses 'the belief that outcomes of a random event shall "even out" within a small sample').
Nonetheless, the outcomes of the LLN (or rather the lack of it) explained in the comic are far from being rigorously exposed, and may be nearer in spirit to the wrongly intuitive law of averages than to the mathematical exactness you certainly prefer to present in your site.
Off day! was published in Weird Science #17 (jan/feb 1953), written by Al Feldstein and drawn by Jack Kamen.