On Wed, 24 Jan 2001 13:53:25 GMT, "Paolo Covelli" <[EMAIL PROTECTED]>
wrote:
> I know that the techniques as principal component analysis, factor analysis
> or canonical correlation analysis are called R-techniques, because the
> correlation matrix R plays an important role in this approach.
> Instead techniques such as discriminant analysis, cluster analysis or
> multidimensional scaling are known as Q-techniques.
> Why this name?
That's not exactly the way I have seen the distinction.
I am browsing Jum Nunnally, "Psychometric Theory," 1967, page 361.
He describes the usual R technique with Subjects x Variables (rows and
columns, respectively). Correlations are between columns
(variables). P technique has the same person on every row, using
different Periods or points in time.
Q technique is described as concerning correlations among those rows,
and, he says, is sometimes referred to as 'transposed' or 'inverted'
analyses.
The name? Partly because the text goes on to mention O technique,
I suspect that the "Q" name came from splitting the alphabetical
difference between P (with its mnemonic excuse) and R.
--
Rich Ulrich, [EMAIL PROTECTED]
http://www.pitt.edu/~wpilib/index.html
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