Thanks to all who responded to my query:
> A 95% confidence interval for a population mean is well known and often
> calculated as approximately mean +/- 2*(standard-error-of-the-mean).
> My question is, what is the most common and easily understood term for
> an interval with end-points mean +/- 2*SD which will contain 95% of the
> individual values of a population. The ends of the interval are
> estimates of the 2.5 and 97.5 percentiles of the distribution.
The most common suggestion, and the one which I will recommend to my
client is to call this interval a 95% reference interval.
This is the term used in Campbell and Machin - Medical statistics: A
Commonsense approach.
Others suggested the terms reference range or normal range.
Other terms suggested are prediction interval or tolerance interval.
These two terms usually refer to an estimated interval which makes some
allowance for the uncertainty in estimating Mean and SD.
Many respondents pointed out that the reference interval is much more
sensitive to deviations from the Normal distribution than the
confidence interval for the mean.
Thanks again for a rapid and well informed response from the allstat
community.
Tim
--
T R Auton PhD MSc C.Math
Head of Biomedical Statistics
Protherics Molecular Design Ltd
Beechfield House
Lyme Green Business Park
Macclesfield
Cheshire SK11 0JL
UK
email: [log in to unmask]
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|