>Hope you don't mind if I amend these a little,
no I don't mind - esp. when I am wrong ...

>For two-sided interval, if we can assume a normal, n=1 is 68%, n=2 is 95%, n=3 is 99% (these are approx). You could probably use 2 std devs as a 'toss out any othe data' interval, but it depends on your situation.

I new something wasn't right - I just wasn't sure what
thnx for the correction

Arnon