Re: [R] sphericity calculation

From: Uwe Ligges <ligges_at_statistik.uni-dortmund.de>
Date: Wed 11 May 2005 - 17:28:13 EST

Darren Weber wrote:

> Dear Prof. Baron,
>
> thankyou for your pdf paper on using R, at
>
> http://www.psych.upenn.edu/~baron/rpsych.pdf
>
> I am currently interested in the sphericity notes on pp. 45-47.
>
> The equation on p. 46 suggests the following R calculation:
>
> D <- k^2 * ( mean(diag(S)) - mean(S) )^2
>
> while the notes in the pdf indicate the following:
>
> D <- k^2 * ( mean(S) - mean(diag(S)) )^2
>
> Can you please consider this and advise the correct calculation?

Both are equal! Mathematical calculations you should really know from school show that
(a - b)^2 = (b - a)^2
.....

Uwe Ligges

> Best, Darren
>
> [[alternative HTML version deleted]]
>
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R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed May 11 17:32:12 2005

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