From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>

Date: Sun, 06 Apr 2008 07:12:43 +0100 (BST)

Date: Sun, 06 Apr 2008 07:12:43 +0100 (BST)

Why do you keep posting something to which you have already received an answer?

https://stat.ethz.ch/pipermail/r-help/2008-April/158662.html
answered in

https://stat.ethz.ch/pipermail/r-help/2008-April/158664.html

and repeated at

https://stat.ethz.ch/pipermail/r-help/2008-April/158787.html
and

https://stat.ethz.ch/pipermail/r-help/2008-April/158796.html
(this message).

All of these are with unwrapped lines (I wrapped the version below) and contain HTML which the posting guide asked you not to send.

On Sat, 5 Apr 2008, Ray Haraf wrote:

> Dear All,

*>
**> I would be very appreciative of your help with the following
*

But you then showed 0% appreciation of the help you were given!

> 1). I am running multivariate multiple regression through the manova()

*> function (kindly suggested by Professor Venables) and getting two
**> different answers for test=c("Wilks","Roy","Pillai") and
**> tests=c("Wilks","Roy",'"Pillai") as shown below. In the first case
**> (test=c(list)) I got error message which probably means I can only call
**> one test at a time. I thought I could get ride of this by adding "s" to
**> test; in this case (tests=c(list)), I got Pillai test. Does this mean
**> that Pillai would be the default test and summary(manova()) can only
**> post one test at a time?
**>
**>> summary(manova(cbind(y1, y2) ~ z1, data =
**> + ex7.8),test=c("Wilks","Roy","Pillai"))
**> Error in match.arg(test) : 'arg' must be of length 1
**>> summary(manova(cbind(y1, y2) ~ z1, data =
**> + ex7.8),tests=c("Wilks","Roy","Pillai"))
**> Df Pillai approx F num Df den Df Pr(>F)
**> z1 1 0.9375 15.0000 2 2 0.0625 .
**> Residuals 3
**> ---
**> Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
**>
**> 2). My next struggle is to construct prediction ellipse. Both ellipse()
**> and ellipse.lm() are not giving me the solution to "Sampling from
**> multivariate multiple regression prediction regions" posted by Iain
**> Pardoe, Mon May 9 18:43:46 2005. I am working on the same problem and
**> performed all the steps he suggested
**>
**>> ex7.10 <-
**> + data.frame(y1 = c(141.5, 168.9, 154.8, 146.5, 172.8, 160.1, 108.5),
**> + y2 = c(301.8, 396.1, 328.2, 307.4, 362.4, 369.5, 229.1),
**> + z1 = c(123.5, 146.1, 133.9, 128.5, 151.5, 136.2, 92),
**> + z2 = c(2.108, 9.213, 1.905, .815, 1.061, 8.603, 1.125))
**>> attach(ex7.10)
**>> f.mlm <- lm(cbind(y1,y2)~z1+z2)
**>> y.hat <- c(1, 130, 7.5) %*% coef(f.mlm)
**>> round(y.hat, 2)
**> y1 y2
**> [1,] 151.84 349.63
**>> qf.z <- t(c(1, 130, 7.5)) %*%
**> + solve(t(cbind(1,z1,z2)) %*% cbind(1,z1,z2)) %*%
**> + c(1, 130, 7.5)
**>> round(qf.z, 5)
**> [,1]
**> [1,] 0.36995
**>> n.sigma.hat <- SSD(f.mlm)$SSD # same as t(resid(f.mlm)) %*%resid(f.mlm)
**>> round(n.sigma.hat, 2)
**> y1 y2
**> y1 5.80 5.22
**> y2 5.22 12.57
**>> F.quant <- qf(.95,2,3)
**>> round(F.quant, 2)
**> [1] 9.55
**>
**>
**>> From here how could I calculate a 95% prediction ellipse for y=(y1,y2)
**>> at (z1,z2)=(130,7.5) using either ellipse or ellipse.lm? y1 would be
**>> the x-axis and y2, the y-axis. The center is different from (0,0) and I
**>> don't know what would be the appropriate x (the lm object). Should I
**>> used predicted values or residuals? In both cases I have vectors which
**>> is different from the example given with ellipse.lm
**>
**> 3). Lastly but not the least, would be too ambitious to draw the axes
**> (i.e, the eigenvalues) to the ellipse?
**>
**> Thanks and very kind regards,
**> Ray
**>
**> [[alternative HTML version deleted]]
**>
**> ______________________________________________
**> R-help_at_r-project.org mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
**> and provide commented, minimal, self-contained, reproducible code.
**>
*

-- Brian D. Ripley, ripley_at_stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-help_at_r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.Received on Sun 06 Apr 2008 - 06:14:42 GMT

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