Article View: sci.math.stat
Article #387Re: 1) Bootstrap 2) Standard deviation
From: J E H Shaw
Date: Mon, 17 Aug 1992 17:27
Date: Mon, 17 Aug 1992 17:27
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1874 bytes
1) Most statistical methods attempt to generalise from a set of data
by making assumptions about the underlying population (e.g. `Normal
with unknown mean & variance'), estimating the unknown parameters
(here mean & variance) and using the properties of the fitted
distribution (here Normal) to, for example, predict future data.
`Bootstrapping' goes straight for the jugular (bypassing the brain
almost entirely :-) and uses the observed data distribution as an
estimate of the population distribution (i.e. probability mass 1/N
at each of the N data points). Properties of the assumed underlying
population are inferred from the corresponding data properties.
(And if it's too hard to do analytically, simulate by generating
further `bootstrap samples' from the data distribution).
Bootstrapping is the ultimate in maximum likelihood estimation
(attempts to produce a Bayesian analogue are, IMHO, weird).
2) Biasedness of the SD is hardly mentioned because it's too hard.
(And in almost any practical analysis, biasedness is the least
of my worries anyway).
-- Ewart Shaw
--
J.E.H.Shaw, Department of Statistics, | JANET: strgh@uk.ac.warwick.cu
University of Warwick, | BITNET: strgh%uk.ac.warwick.cu@UKACRL
Coventry CV4 7AL, U.K. | PHONE: +44 203 523069
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Path: arc1-ca.pugleaf.net!sparky!uunet!mcsun!uknet!warwick!strgh From: strgh@warwick.ac.uk (J E H Shaw) Newsgroups: sci.math.stat Subject: Re: 1) Bootstrap 2) Standard deviation Message-ID: <5j9nb03z@csv.warwick.ac.uk> Date: 17 Aug 92 17:27:31 GMT References: <1992Aug14.193227.9029@spss.com> Sender: news@csv.warwick.ac.uk (Network news) Organization: Computing Services, Warwick University, UK Lines: 27 Nntp-Posting-Host: clover