On Wed, 17 Dec 2008 at 12:08:18, Graham Easterling
wrote in uk.sci.weather :

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.

I was always told that you mustn't quote an average to a greater
precision than the accuracy of the instrument. That doesn't necessarily
mean I abide by that, though...
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)