Yes, it does mean you can only get one kind of test at a time. If you want more than one kind of test, you have to do it separately. The simplest way to do this is probably something like this:
M_obj <- manova(cbind(y1, y2) ~ z1, data = ex7.8) for(test in c("Wilks", "Roy", "Pillai")) print(summary(M_obj, test = test)) Further, I do not anticipate R will change to make this sort of thing any easier. I know some of the big guys offer multiple kinds of test all at once, no questions asked, presumably to allow the user to pick and choose post hoc. Perhaps we can persuade them to adopt better practices in future, but somehow I doubt it. Bill Venables CSIRO Laboratories PO Box 120, Cleveland, 4163 AUSTRALIA Office Phone (email preferred): +61 7 3826 7251 Fax (if absolutely necessary): +61 7 3826 7304 Mobile: +61 4 8819 4402 Home Phone: +61 7 3286 7700 mailto:[EMAIL PROTECTED] http://www.cmis.csiro.au/bill.venables/ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ray Haraf Sent: Sunday, 6 April 2008 3:16 AM To: r-help@r-project.org Subject: [R] summary(object, test=c("Roy", "Wilks", "Pillai",....) AND ellipse(object, center=....) Dear All, I would be very appreciative of your help with the following 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@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. ______________________________________________ R-help@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.