Four shuffles suffice

It takes a while to shuffle a deck of cards seven times, but it is well known that that is how many riffle shuffles it takes to fully randomize a deck of 52 standard playing cards. This was shown in 1992 by Bayer and Diaconis. As it turns out, however, for some games fewer than…

Judges, sonar, and innumeracy

Good Math, Bad Math has an interesting blog postĀ about the recent Supreme Court caseĀ over the Navy’s use of sonar near marine wildlife. In the blog (and in the readers’ comments that follow), they talk about Chief Justice John Roberts use (misuse) of mathematics in his written decision.