Comments on: Charles Murray is Da Bomb

By: Kevin

Kevin — Mon, 22 Dec 2008 02:23:24 +0000

I agree with FedUp Mom—averages are only appropriate when the quantity being measured is on an additive scale and are only a good measure of central tendency when the distribution is nearly symmetric.

The raw results of tests are often quite a skewed distribution, so that the arithmetic average is not a good measure of central tendency.

Of course, lots of people use the terms “above average” and “below average” very loosely, and there is not much to be gained by insisting on precision for these somewhat vague terms.

By: FedUpMom

FedUpMom — Sun, 21 Dec 2008 17:43:12 +0000

I stand by my statement. If you’re talking about a “normed” test, then the term Murray should be using is “percentile”, as in “half of all kids are below the 50th percentile”. It confuses the issue to call it an “average”, and contributes to the innumeracy of our culture.

BTW, these “normed” tests can’t distinguish between “very bright” and “profoundly gifted”, because they all test out at the 99th percentile. But within those 99th percentile kids, there’s a wide variety of abilities, which call for different kinds of education. That’s a big topic of discussion for gifted advocates.

By: N. Green

N. Green — Tue, 30 Sep 2008 06:16:20 +0000

This is a comment on an Aug. 20 post by “FedUpMom”.

When there is a very large sample of measurements, and when one is deriving a statistical mean for normalized data, then it is quite legitimate to suggest that “50%” of children are below average. The midpoint of a normal distribution is what Murray is referring to when he calls 50% the average point. The percentage of data points below that point is exactly equal to the percentage of data points above.
So, sorry, but 50% of children produce IQ (and SAT) scores that are BELOW AVERAGE.

By: SwitchedOnMom

SwitchedOnMom — Fri, 22 Aug 2008 15:16:37 +0000

There is another (shorter) article about his views on gifted education: “With a High IQ Comes Need for Special Education”

http://www.aei.org/publications/filter.all,pubID.26605/pub_detail.asp

By: SwitchedOnMom

SwitchedOnMom — Fri, 22 Aug 2008 15:14:46 +0000

Good call Fed Up Mom!

By: Cate

Cate — Thu, 21 Aug 2008 09:20:56 +0000

I went to see him last year when he was visiting Australia, and gave a copy of his article to our Principal. Powerful stuff!

By: FedUpMom

FedUpMom — Wed, 20 Aug 2008 20:48:06 +0000

It is not true that 1/2 of all children are below average. 1/2 of all children are below the median, by definition. But that’s not how the average works. An average is the sum of all measurements, divided by the number of measurements.

One of my favorite stats is that the average height for American women is 5’4”, but the majority of American women are below the average height. In other words, there’s a few 6-foot women who hike the average up.

By: KarenDV

KarenDV — Wed, 20 Aug 2008 12:24:16 +0000

Thanks for this — I’ve linked to this post on my blog.