Displaying 20 results from an estimated 5000 matches similar to: "How to do Hotelling's t2 test?"
2007 Feb 20
1
Mahalanobis distance and probability of group membership using Hotelling's T2 distribution
I want to calculate the probability that a group will include a particular
point using the squared Mahalanobis distance to the centroid. I understand
that the squared Mahalanobis distance is distributed as chi-squared but that
for a small number of random samples from a multivariate normal population
the Hotellings T2 (T squared) distribution should be used.
I cannot find a function for
2016 Apr 08
3
Generating Hotelling's T squared statistic with hclust
I am doing a cluster analysis with hclust. I want to get hclust to output the Hotelling's T squared statistic for each cluster so I can evaluate is data points should be in a cluster or not. My research to answer this question has been unsuccessful. Does anyone know how to get hclust to output the Hotelling's T squared statistic for each cluster?
Mike
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2012 Feb 09
1
Hotelling T2 test extension for multigroup data
Hi all,
I've got the following matrix :
?
mat <- matrix(rnorm(700), ncol=5, dimnames=list( paste("f", c(1:140), sep="_"), c("A", "B", "C", "D", "E")))
I can see that currently most of the multivariate Hotelling T2 tests are limited for application on two groups/samples.
I wud appreciate if someone can provide me a
2005 Jan 27
2
Results of MCD estimators in MASS and rrcov
Hi!
I tested two different implementations of the robust MCD estimator:
cov.mcd from the MASS package and
covMcd from the rrcov package.
Tests were done on the hbk dataset included in the rrcov package.
Unfortunately I get quite differing results -- so the question is whether
this differences are justified or an error on my side or a bug?
Here is, what I did:
> require(MASS)
>
2007 Jun 08
1
Need Help with robustbase package: fitnorm2 and plotnorm2
This is my first post requesting help to this mailing list. I am new
to R. My apologies for any breach in posting etiquette. I am new to
this language and just learning my way around. I am attempting to run
some sample code and and am confused by the error message:
Loading required package: rrcov
Error in fitNorm2(fdat[, "FSC-H"], fdat[, "SSC-H"], scalefac = ScaleFactor) :
2003 Feb 19
1
getting/storing the name of an object passed to a function
Hi
I have a couple of functions that work on the object created by another R
command and then print out or summarise the results of this work.
The main function is defined as:
hotelling.t <- function(obj)
{
#internal commands
}
I then have print.hotelling.t() that takes the list returned by hotelling.t
and prints it with some extra significance calculations, formatting, etc.
I want to
2005 Jun 21
1
test for equality of two data sets with multidimensional variables
Hello there,
I have two data sets with 14 variables each, and wish to do the test
for equality of their covariance matrices and mean vectors. Normally
these tests should be done by chi square test (box provided) and
Hotelling's T square test respectively. Which R functions could do
this kind of test? I just find some functions could do for one
dimension, but no for multidimension. Some one
2010 Dec 26
1
T2 hoteling
Dear All
It is very kind of you to guide me.
When I want to run this line, I see this error
stat.obs <- apply(GS, 2, function(z) Hott2(t(DATA[which(z==1),]), cl))
Error in colSums(w * x) : 'x' must be an array of at least two dimensions
cl <- as.factor(y)
GS: a matrix with 0 or 1
GS: gene sets
-> a data matrix with rows=genes,
columns= gene sets,
GS[i,j]=1 if gene i in
2011 Jul 13
2
Package rrcov, functions PcaCov, PcaHubert, PcaGrid
Hello,
I'm using the R-2.13.1 version in Windows and I'm trying to do a robust Pca
with the following:
x<-matrix(0.5,30,30)
library("rrcov")
y<-PcaCov(x)
The following error occurs:
Error: diff(sv)<0 ist not all TRUE
The same error occurs with the other functions. What does this mean and how
can I perform the robust PCA with these functions by using a quadratic
2014 Sep 26
1
Why is my R package still compiling with the O2 flag?
When I install an R package with cpp codes such as rrcov via CRAN (under
R 3.1.1, using no Makevars file and under Ubuntu 14.04 using GCC 4.8),
the cpp code is compiled with the -o3 flag (in fact, looking at the
Makeconf file this seem to again be the default since R 3.1.1) But when
I install my own package via CRAN it is compiled with the -o2 flag.
My questions are what is causing my
2012 Apr 16
2
Problems with subset, droplevels and lm: variable lengths differ
[Env: R 2.14.2 / Win Xp]
In the script below, I want to select some variables from
rrcov::OsloTransect, delete cases with
any missing data, and subset the data frame Oslo to remove cases for two
levels of the
factor litho that occur with low frequency.
The checks I run on my new data frame Oslo look OK, but I when I try to
fit a multivariate
linear model with lm(), I am getting an error:
1998 Nov 16
0
Re: Hotelling corrected
By accident, I left out the lines defining n1 and n2. Here it is as a
function.
Peter B.
hotelling <- function(d1,d2){
k <- ncol(d1)
n1 <- nrow(d1)
n2 <- nrow(d2)
xbar1 <- apply(d1,2,mean)
xbar2 <- apply(d2,2,mean)
dbar <- xbar2-xbar1
v <- ((n1-1)*var(d1)+(n2-1)*var(d2))/(n1+n2-2)
t2 <- n1*n2*dbar%*%solve(v)%*%dbar/(n1+n2)
f <-
2007 Apr 15
4
Hotelling T-Squared vs Two-Factor Anova
Hi,
I am a graduate student at Stanford University and I have a general
statistics question. What exactly is the difference between doing a
two-factor repeated measures ANOVA and a Hotelling T-squared test for
a paired comparison of mean vectors?
Given:
Anova: repeated measures on both factors, 1st factor = two different
treatments, 2nd factor = 4 time points, where you are measuring the
blood
2009 May 26
2
(OT) Does pearson correlation assume bivariate normality of the data?
Dear all,
The other day I was reading this post [1] that slightly surprised me:
"To reject the null of no correlation, an hypothsis test based on the
normal distribution. If normality is not the base assumption your
working from then p-values, significance tests and conf. intervals
dont mean much (the value of the coefficient is not reliable) " (BOB
SAMOHYL).
To me this implied that in
2011 May 15
0
hotelling and confidence region
Good morning
I've made an PCA and I'd like to plot a confidence region based on Hotelling
T2? Does anyone know how to compute it?
Thank you
--
View this message in context: http://r.789695.n4.nabble.com/hotelling-and-confidence-region-tp3524204p3524204.html
Sent from the R help mailing list archive at Nabble.com.
1998 Nov 16
1
PB Mandeville can't be reached
# Peter B. Mandeville kindly offered to send me code for Hotelling's T^2
# Test. Unfortunately there seems to be no route to his machine.
# So i'm trying to reach him via the Mailing List.
------------------------------------------------------------------------
Sir,
this morning i recieved your message about the availability of the code
for Hotelling's Test. I hurried to find out
1998 Nov 11
1
MANOVA / Hotelling's Test
Hi everybody ...
I have to perform Hotteling's T^2 Test - more generally a MANOVA - on a
set of data. Is there a (simple?) possibility to do it in R?
The somewhat obvious way to do it would be
> summary(aov(Y ~ x1 + x2 ... + xn))
where Y would be a two-column matrix.
But this does not work in any possible combination of matrix or factor
dimensions! Is it principally not possible
2012 Mar 16
1
Change in behavior of update.views()?
I haven't seen this cryptic warning before:
> update.views('Robust')
Warning message:
In update.views("Robust") :
The following packages are not available: covRobust, distr, FRB, MASS, mblm, multinomRob, mvoutlier, quantreg, RandVar, rgam, RobAStBase, robfilter, RobLox, RobRex, robust, RobustAFT, robustbase, ROptEst, ROptRegTS, rrcov, sandwich, wle
>
2011 May 16
1
help: Using hotelling for a confidence region for PCA scores
Hello everyone.
In my last post I did not explained my problem quite well. I made a principal component analysis and took the 2 first principal components. I made a chart of my points based on the score of the 2 PC. I would like to add on this graph a 95% confidence region. To do this I used the ellipse function as follows:
pcsref=PC$score[data[,1]==ref,1:2] #matrix containing the scores
2010 May 27
1
library installation problem, invalid regular expression in help indices
Hi,
I have a strange package installation problem after update to R 2.11.0
on Fedora Core 12.
A colleague of mine with the very same Fedora and R versions doesn't
have this problem, while logging on to his computer but installing from
my settings and into my local library path also shows the problem, so it
seems to be related to some of my environment settings.
Installation of several