#5. What We Call “Average” Actually Isn’t
The problem is that averages are absolutely useless if a minority of numbers are unusually high — the average of 1, 2, 3, 4, and 40 is 10, which doesn’t help anybody know about anything.
For instance, you can see one study showing that for every 100 Americans, there are 88 guns, which could lead someone to reasonably assume that it’s hard to find an American who isn’t packing heat. Then you see another study from the same year showing that only 43 percent of households have guns in them. It’s the same deal — the people who have tons of guns skew the average upward … and in the process make it hard as hell to get an idea of the overall picture. More often than not, telling us the average just muddles the issue.
#4. A Claim of “99 Percent Accurate” Can Be Both True and Meaningless
What you have come down with is instead an acute case of base-rate fallacy. For example, in the U.S., the Transportation Security Administration a few years ago started talking up their new terrorist screening technology. They claimed it could catch over 99 percent of terrorists that pass through, while only identifying 0.01 percent of innocent people as al-Qaida operatives.
Those numbers sound fantastic, but as with our cancer example, this means that a gigantic number of innocent people are getting treated as terrorists. So for instance, in 2010, about 700 million times, somebody boarded a plane that flew in the USA. If their terrorist detector “only” throws out positives 0.01 percent of the time, that means 70,000 fucking people are getting pulled out of line, accused, and searched. And in most years, statistically 0 percent of those people are terrorists. So that 0.01 percent sounds great, until you’re the one they accuse of having a tiny bomb wedged in your rectum.
#3. Claiming to Be the “Fastest Growing” Group/Company/Etc. Might Not Be All That Impressive
going by the rate of change isn’t that helpful. If the bacon-based cult that your crazy uncle and his four friends invented gains two members at the local country club, then the Church of Baconism just grew by 40 percent.
“But Cracked,” someone is already saying, “the fact that they’re the fastest growing still means that if current trends continue, they’ll eventually be number one!”
Right, if current trends continue. But current trends don’t always continue, otherwise the alarmists would have no reason to be alarmed — their whole reason for freaking out is that some prior trends didn’t continue. The point is, any time you hear a company boasting of being the “fastest growing,” you should take a moment to find out if they mean they just increased their workforce from three to six people before you invest.
#2. What They’re Calling an “Epidemic” May Actually Be Random Chance
The truth is that in a large enough population, you’re going to get random patterns — especially if you give yourself infinite room to find similarities. For instance, the above study may also have found that kids living near power lines are 5 percent more likely to be named “Steve,” or that they are 3 percent more likely to prefer red bicycles. When you’re talking about tiny differences, you can find all sorts of weird-ass connections. So, they found that in some areas, kids were up to four times as likely to have leukemia (holy shit! Power lines are murdering our children!), but they ignored the fact that in other areas, the kids were actually less likely to have it (holy shit! Power lines have magical healing abilities!). In reality, it was all averaging out.
#1. Correlation Does Not Equal Causation
The difference is that until you know how television is murdering you, all you know is that television and death are related in some way. There’s no way to tell whether watching a lot of television and dying a little earlier are both symptoms of something else.
And that, by the way, seems to be exactly what’s going on here — it turns out that people who don’t like exercise tend to reach for hobbies that don’t involve moving (like television), and not getting enough exercise is what’s killing us. Which is to say, reading a book is much more deadly than watching TV on a stationary bike.
Read more at http://www.cracked.com/article_20318_the-5-most-popular-ways-statistics-are-used-to-lie-to-you.html