On 08/12/10 17:51, prodata wrote:
On Dec 8, 3:19 pm, wrote:

I've calculated the December mean from 1971 - 2009 as +5.0c, with a
Standard Deviation of 1.5c, so by my calculations the current CET that
is running at -2.0c is somewhere between 4& 5 Standard Deviations.

Is there evidence that these values are normally distributed? Maybe
this has been throughly tested and is well-known? But if not then
personally I'd be happier with a non-parametric analysis.

JGD

Technically speaking they won't be, as the normal distribution is
unbounded, whereas there is a limit on how large a magnitude a
temperature anomaly can be. However for practical purposes it is likely
that temperature anomalies will be close enough to normal that the usual
statistical techniques that require normality will be valid.