EXAMPLE 9 Oh, those percents

Here are a couple of examples involving percents. During the December 4, 2009, episode of the TV show Fox & Friends, a graphic was displayed with the question heading: “Did scientists falsify research to support their own theories on global warming?” The results, attributed to a Rasmussen Reports Poll on global warming, indicated that 59% of people believed this was “somewhat likely,” 35% thought it was “very likely,” and 26% considered it “not very likely.” That adds up to a whopping 120% of those polled! Turns out that Fox & Friends misquoted the actual Rasmussen Reports Poll results but didn’t notice the error.

Even smart people have problems with percentages. A newsletter for female university teachers asked, “Does it matter that women are 550% (five and a half times) less likely than men to be appointed to a professional grade?” Now 100% of something is all there is. If you take away 100%, there is nothing left. We have no idea what “550% less likely” might mean. Although we can’t be sure, it is possible that the newsletter meant that the likelihood for women is the likelihood for men divided by 5.5. In this case, the percentage decrease would be