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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
R: R: Averaging
From: Federico Rossi
Date: 2004 Oct 19, 10:55 +0200
From: Federico Rossi
Date: 2004 Oct 19, 10:55 +0200
George, I agree with your considerations. I'll try to dig in my books and find out if a more convincing explanation can apply. Federico Rossi -----Messaggio originale----- Da: Navigation Mailing List [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM] Per conto di George Huxtable Inviato: marted? 19 ottobre 2004 0.44 A: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM Oggetto: Re: R: Averaging Federico Rossi wrote, about averaging an odd number of observations- >The explanation I've found for this recommendation is that this way you >can consider the central value of the odd series (i.e. the so called >median) which is definitely less affected by abnormal values than the >average value. ================= Selecting a median that way seems to be an alternative to averaging. It's a rather extreme case of discarding outliers, in that it discards EVERYTHING but the one median observation. I can see that it might be usable (if not ideal) for dealing with a quantity that fluctuates in a random manner. But I don't see how you would apply that technique to a quantity that was changing systematically, in the way that observed altitudes change rather steadily with time (either increasing or decreasing), with a bit of random scatter superimposed. George. ================================================================ contact George Huxtable by email at george@huxtable.u-net.com, by phone at 01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. ================================================================
