Carl Bialik ponders unlikely events:

Jessica Utts, the author of “Seeing Through Statistics,” cautions that events that seem unlikely at first glance may not be that unlikely given enough opportunity. For example, Utts says, if everyone dreamed about a plane crash once in their lives, a few thousand people would have the crash dream on any given night including the night of a crash.

“These specific incidences may be unlikely, but the combined probability of something similar at some point in time is probably fairly high,” Utts, a statistician at the University of California, Irvine,said about the recent collisions.

We tend to fixate on those events that are memorable, after they happen. Peter H. Westfall, a statistician at Texas Tech University, notes that any given order of a shuffled 52-card deck has about a one in 10 to the 68th power probability of happening, including the sequence in which all 52 cards appear in order. “Everything we see has about a zero probability,” Westfall said. “Calculating these probabilities after the fact is kind of meaningless.”