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dpb

On 9/28/2013 4:36 PM, wrote:
On Sat, 28 Sep 2013 16:21:34 -0500, wrote:

On 9/28/2013 2:04 PM, wrote:
...

Only if the distribution is normal (and symmetrical).

A normal (Gaussian) is symmetrical by definition.

When is the arithmetic mean not the average, again?

Sorry, but I meant that not half the people are above average. Half
of a distribution is above MEDIAN, but not necessarily the mean.

Garrison says all are above average...

All I know about indicates that population sample of IQs isn't
demonstrable as _not_ following a normal distribution; if that is so
then it is so that as well as can be determined there are as many above
the mean as below...

I just did a _very_ quick search and didn't find anything convincing
that the assumption isn't so; I did find the following abstract --

Does the Normal Curve Accurately Model the Distribution of Intelligence?
Lindsey R. Godwin, Kyle V. Smith

Like many human characteristics, intelligence is theorized to be
normally distributed. However, a vocal minority of researchers and
practitioners who study individuals with high intelligence have
claimed that there are more people in the upper echelons of
intelligence than would be expected if the normal curve accurately
modeled the distribution of intelligence scores.1,2,3,4

To verify this claim we carefully searched articles from the journal
Intelligence dated 1979 to 2012, completed an academic journal
search and reviewed national data sets for samples that permit this
claim to be tested. ... We reviewed the information provided from
these sources and determined that intelligence is indeed normally
distributed.

Of course, if the claim of the "vocal minority" were so, it would lead
to a skewed distribution to the right, not the left.

--