Saturday, June 13, 2009

What Are the Odds?

Here's a feature of the Sonia Sotomayor nomination that isn't getting a lot of play: if she is confirmed, eight out of nine Supreme Court Justices will be either Catholic or Jewish.

How unlikely is that? According to the Gallup Organization, Catholics and Jews together make up about 27% of the national population (see table 80 after clicking the link).

Now a little math: if Justices were chosen at random from the national popultion, the probability that any specified 8 out of the 9 justices would fall within this group would be (.27)^8 = 0.0000282. But then there are 9 possible ways to take 8 Justices out of 9, so the possibility that any 8 out of the 9 would be either Catholic or Jewish is 9 * (.27) ^8 = .000254. In other words, about 1 chance in 4000.

This calculation is a little artificial in that it chooses one particular moment (the moment after Judge Sotomayor's hypothetical confirmation) to do the calculation. Really, one should ask what the likelihood is that, at some point in our 200+ year history, we would find 8 out of 9 Supreme Court Justices in these categories. That's too complicated (for me, anyway), but suffice it to say that, while the probability would be higher than 1 in 4000, it would still be a surprise.

What does all this mean? Not much, probably. But it is somewhat surprising. One is tempted to think that there must be something about Catholics and Jews that disproportionately propels them toward careers that could lead to a Supreme Court appointment.

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