Back to basics: multivariate qualitative analysis, canonical variates analysis

Columns

01 Aug 2008

A.M.C. Davies^a and Tom Fearn^b
^aNorwich Near Infrared Consultancy, 75 Intwood Road, Cringleford, Norwich NR4 6AA, UK. E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
^bDepartment of Statistical Science, University College London, Gower Street, London WC1E 6BT, UK. E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Introduction

In our previous column we introduced some distance statistics that have been used for comparing spectra. These calculations provide univariate answers from multivariate data in a single step. This may be adequate for some problems but often we need to employ some multivariate mathematics before the reduction to a univariate answer.

This column is an introduction to the first method, which was invented long before chemometrics by R.A. Fisher; some seventy years ago! Canonical Variates Analysis (CVA)2 has been one of my favourite examples of chemometrics because it often requires the use of a compression technique (PCA or FFT for example) before it can be applied and I think it helps students to understand the need to know the essential properties of the different tools in the chemometric toolbox.
Tony Davies

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