On Sat, 28 Sep 2013 16:21:34 -0500, dpb 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.