``With a large enough sample, almost any outrange thing is likely to happen."
This is the Law of True ly Numbers, as enunciated by Diaconis and Mosteller
(*JASA, * 1989). In operation, its results are always surprising to the
man in the street. Coincidences and patterns of events that are predictiable
-and in large samples nearly guaranteed by - the laws of probability seem
too implausible to be arributed to mere chance. This gives rise to the tendency
seek explanation in terms of predestination, EPS, etc.

The goal of this unit in the CHANCE course is to debunk the outrageously high odds that are commonly reorted in news reports when a surprising event occurs. Also, since, statistical tests of significance are based on calculating how unlikely certain observations would be based chance alone, discussion of coincidences can provide a usuful vocabulary fram ework and help to sharpen intuitive notions.