Old joke: Man walks
into a working class bar where seven men are hunched over beers. The average net worth in the bar is now seven
billion dollars. Who is the man? Answer, Bill Gates. You would think that by now people would
understand the difference between the mean, or average, and the median, the
point in a linear array of items midway between those below and those above, on
some scale of measurement.
Well, good old MSN has screwed it up, and not, I think, by
accident. They have a story on their
website about a list of twenty-one jobs that pay the average wage of roughly
$24 an hour, or more than $48,000 a hear.
Pretty good looking jobs, I must say.
The only problem is that the median
wage is a bit more than $13.50 an hour, or $27,500 a year. Fully half
of all the full-time employed men and women in the United States make less than
that. HALF. The average is pulled
way above the median by the high wages of people at or near the top of the
income pyramid [including me, when I was working as a senior professor, and all
the other senior professors at American
universities.]
Now, that isn't so hard to understand, is it?
As I like to point out to my classes occasionally it may be that not all the children are above average, of necessity; but it can be that all but one are.
ReplyDeleteAlas, David, in my experience, it is more than likely that all but one are below average!
ReplyDeleteI once had to explain why averages can be misleading. I used the following story:
ReplyDeleteYou and I go out for lunch. We order a BBQ chicken and two beers. I have the whole stuff, while you stand there.
When I finish I ask you for half the bill. After all, on average we both had half a chicken and one beer...
seems fair. :)
ReplyDeleteIt gets even worse when trying to explain why it is possible that:
ReplyDelete1. A tax cut can hugely favor the rich AND
2. The rich still wind up paying a larger share of total taxes
The missing piece of the picture is that the rich have ALSO gotten such a huge increase in income.
The best "story" version of this I have come up with (and it is still lame) is: "my boss got both the biggest raise AND the biggest tax cut. But the raise was so HUGE that he still wound up paying a little more in taxes."
I think inequality of income stems in no small part from the strong human tendency to innumeracy. Unequal ability to understand numbers yields unequal ability to count money, and from there you quickly get to unequal ability to accumulate the stuff.