Greetings, numbers fans. I’m filling in for Carl, who is taking a well deserved vacation from numerical sleuthing.
But can we really know that there are 96.6 million U.S. Internet users who read a blog once a month? Highly doubtful. So why not just say 97 million? Or 100 million? Is the Energy Information Administration really confident that there are 117.064 billion barrels of proven oil reserves in Africa? No, it isn’t. But still the decimal places persist. The lure of their aura of authenticity, their veneer of verisimilitude, is just too great.
The precision fetishism cropped up recently when the Environmental Protection Agency changed the list of cars eligible to be junked for bucks in the cash-for-clunkers program. The agency said “more precise” data calculated “to four decimal places” caused the revisions. But how accurate can fuel-economy calculations be? Not that precise: 0.0001 miles is about six inches.
Sometimes, the parade of decimal places comes from running afoul of the rule of significant digits, a precept drummed into every high-school chemistry student. But apparently often forgotten.
In the column, I also write about a would-be Alaska lawyer, Frank Bettine, who sued the Alaska Bar Association, claiming that too many decimal places were used in scoring his bar exam. (He failed.) The court rejected his appeal, though it found his critique “convincing from a purely mathematical standpoint.”
Readers, what are your faux-exact peeves?