The majority of data sets collected byresearchers in all disciplines are multivariate.
In a few cases it may be sensible to isolate each variable and study it separately, but
in mostcases all the variables need to be examinedsimultaneously in orderto fully
grasp the structure and key features of the data. For this purpose, one or another
methodof multivariateanalysis mightbe mosthelpful,and it is with such methods
that this bookis largely concerned.
Multivariateanalysis includes methods both for describing and exploringsuch
data and for makingformal inferences about them. The aim of all the techniques
is, in a generalsense, to displayor extract the signal in the data in the presence of
noise, and to find out whatthe data show us in the midstof their apparent chaos.
The computations involved in applying mostmultivariatetechniques are con-
siderable,and their routine use requires a suitable software package. In addition,
mostanalyses of multivariatedata should involve the construction of appropriate
graphs and diagrams and this will also need to be carried out bythe samepackage. R
and S-PLUS@are statistical computing environments, incorporating implementa-
tions of the S programming language. Bothare powerful,flexible, and, in addition,
have excellent graphical facilities. It is for these reasons that they appear in this
book. R is available free through the Internet under the GeneralPublic License; see
R Development CoreTeam (2004), R: A Languageand Environment for Statisti-
cal Computing,R Foundation for StatisticalComputing,Vienna,Austria,or visit
their websitewww.R-project.org. S-PLUS is a registered trademark of Insightful
Corporation,www.insightful.com.Itis distributed in the United Kingdom by
Insightful Limited
5th Floor
Network House
Basing View
Basingstoke
Hampshire
RG214HG
Tel: +44 (0) 1256339800
vii
扫码加好友，拉您进群
全部版块
我的主页
收藏
