On 17 Dec, 18:54, Pete L wrote:
On 17 Dec, 17:19, Mike Tullett wrote:





On Wed, 17 Dec 2008 07:39:37 -0800 (PST), Pete L wrote in


http://newsvote.bbc.co.uk/2/hi/scien...re/7786060.stm

Just looking at the figures on the above link.....

Can anybody explain how and why two significant decimal places are
considered? As far as I recollect an ordinary mercury thermometer is
accurate to 0.2 deg. So to suggest global mean temperatures are 14.31
degs seems totally meaningless. I would have though just 14 degs is
enough without trying to invent a greater accuracy.

I think that precision is justified when it is based on hundreds or
thousands of mean temperatures.

--
Mike Tullett - Coleraine 55.13°N 6.69°W *posted 17/12/2008 17:19:42 *GMT

So, you suggest that the error cancels itself out with thousands of
mean temps? That supposes that there is an equal number of
thermometers reading high and low. Seems a bit unlikely.- Hide quoted text -

- Show quoted text -

It does minimise the error. I read my barometer to the nearest mb. If
I had 1,000 barometers calibrated to the same standard, and managed to
read them all at the same time, and took the mean, it would be
reasonable to quote it to a higher level of precision.

The more readings, the more meaningful the result. So, if the MetO had
sites in St. Mawgan, Falmouth, St Ives, Penzance . . . . . - Sorry, a
brief drift into fantasy.

Graham
Penzance