I don’t expect but maybe one person out of a 1000 to remember the Quadratic Equation—even though my algebra teacher wrote in my yearbook that if I forgot everything else she wanted me to remember that one thing. I don’t expect but maybe one person out of ten to be able count change without a computer someplace in the process. But there is one “math thing” that is starting to annoy me. I’ve heard this one claim for decades and I have never heard anyone else point out the obvious fallacy. It’s like an urban myth that everyone believes even though nearly everyone with a room temperature I.Q. could demonstrate it is false.
What finally tweaked me enough to do something about it was listening to a podcast by someone who claims to be smart enough that he should know better. I’m withholding the name to protect the guilty, but what was said was something like, “80% of the population thinks they are better than average drivers. That’s mathematically impossible!” Grrr…
Try proving that without resorting to a far less common definition of “average”.
A year or two ago in a much different forum someone else made a similar statement about penis sizes. I politely explained they were full of it and it hasn’t come up again (pun intended).
Now, with a much larger audience, I will now explain the issue using different example to (mostly) save you from thoughts about penis dimensions. I hope I don’t have to be subjected to this myth again, and if I am I will be able to just glare at them and send them a link to this post.
Imagine we have a sample of 50 male/female couples. All the people, except one, had their spouse as their one and only sex partner (I told you to imagine, remember?). It turns out that before the age of government education loans and grants Trixie earned her way through medical school the old fashion way—in bed. She had 1000 sexual partners prior to her spouse.
Lets compute the average (usually understood to be the arithmetic mean) number of sexual partners in this sample.
MeanSexualPartners = TotalSexualPartners/NumberOfPeople
MeanSexualPartners = ((99 x 1) + (1 x 1001))/100
MeanSexualPartners = 1100/100
MeanSexualPartners = 11
In this case 99% had 1 sexual partner and can truthfully and correctly state they have had fewer than the average number of sexual partners. Furthermore, 99% can correctly state they have had less than 10% of the average number of sexual partners.
I will leave the drivers and penis dimension examples as exercises for the reader.