Re: [R] p-values and significance

2007-04-11 Thread Bernd Dittmann
Hi Paul, here's a lm model to illustrate this: > summary(lm(y~x.1+x.2)) Call: lm(formula = y ~ x.1 + x.2) Residuals: Min 1Q Median 3QMax -0.0561359 -0.0054020 0.0004553 0.0056516 0.0515817 Coefficients: Estimate Std. Error t value Pr(>|t|)

Re: [R] p values in lme4 package

2007-03-24 Thread Andrew Robinson
Dear Cristina, On Sat, Mar 24, 2007 at 01:51:34PM +0100, Cristina Gomes wrote: > Dear R-users, > I was wondering if anybody knows if it's possible to obtain a p value > for the full model of a GLMM with the lme4 package. I do not believe that it is possible to do so. > I was told that I > sho

[R] p values in lme4 package

2007-03-24 Thread Cristina Gomes
Dear R-users, I was wondering if anybody knows if it's possible to obtain a p value for the full model of a GLMM with the lme4 package. I was told that I should check whether the full model including all the predictor variables is significant before doing stepwise regression or further analysis

[R] p-values for GLMMs

2007-03-23 Thread Cristina Gomes
Hi there, I have a question about the GLMM that I'm doing, that a statistician friend suggested I should have for my analysis. I would like to know if there's any way of obtaining a p value and R square for the full model (and not each variable separately) as to asses whether this model is some

Re: [R] p-values for robust regression

2006-07-05 Thread Martin Maechler
[Oops! Written 6 hours ago, the following was accidentally not sent.] > "Celso" == Celso Barros <[EMAIL PROTECTED]> > on Wed, 5 Jul 2006 04:09:17 -0300 writes: Celso> When I run rlm to obtain robust standard errors, my output does not include Celso> p-values. Is there any r

[R] p-values

2006-07-05 Thread Celso Barros
Dear All, When I run rlm to obtain robust standard errors, my output does not include p-values. Is there any reason p-values should not be used in this case? Is there an argument I could use in rlm so that the output does include p-values? Thanks in advance, Celso [[alternative HTML ver

Re: [R] p values for a GEE model

2006-04-11 Thread Thomas Lumley
On Tue, 11 Apr 2006, Prof Brian Ripley wrote: > On Tue, 11 Apr 2006, Thomas Lumley wrote: >> >> He has a linear model with the same number of observations for each person > > Not so: some have 3 and some have 2, and the two levels of T are not quite > balanced (29/28). > >> and no covariates tha

Re: [R] p values for a GEE model

2006-04-11 Thread Prof Brian Ripley
On Tue, 11 Apr 2006, Thomas Lumley wrote: > On Tue, 11 Apr 2006, Renaud Lancelot wrote: > >> 2006/4/10, Tarca, Adi <[EMAIL PROTECTED]>: >>> Hi all, >>> >>> I have a dataset in which the output Y is observed on two groups of >>> patients (treatment factor T with 2 levels). >>> >>> Every subject in

Re: [R] p values for a GEE model

2006-04-11 Thread Thomas Lumley
On Tue, 11 Apr 2006, Renaud Lancelot wrote: > 2006/4/10, Tarca, Adi <[EMAIL PROTECTED]>: >> Hi all, >> >> I have a dataset in which the output Y is observed on two groups of >> patients (treatment factor T with 2 levels). >> >> Every subject in each group is observed three times (not time points b

Re: [R] p values for a GEE model

2006-04-10 Thread Renaud Lancelot
2006/4/10, Tarca, Adi <[EMAIL PROTECTED]>: > Hi all, > > I have a dataset in which the output Y is observed on two groups of > patients (treatment factor T with 2 levels). > > Every subject in each group is observed three times (not time points but > just technical replication). > > I am interested

Re: [R] p values for a GEE model

2006-04-10 Thread Prof Brian Ripley
On Mon, 10 Apr 2006, Tarca, Adi wrote: > Hi all, > > I have a dataset in which the output Y is observed on two groups of > patients (treatment factor T with 2 levels). > > Every subject in each group is observed three times (not time points but > just technical replication). > > I am interested in

[R] p values for a GEE model

2006-04-10 Thread Tarca, Adi
Hi all, I have a dataset in which the output Y is observed on two groups of patients (treatment factor T with 2 levels). Every subject in each group is observed three times (not time points but just technical replication). I am interested in estimating the treatment effect and take into account

Re: [R] P-values in gls

2006-03-13 Thread Dimitris Rizopoulos
2/(0)16/336899 Fax: +32/(0)16/337015 Web: http://www.med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm - Original Message - From: "Wilson, Andrew" <[EMAIL PROTECTED]> To: Sent: Monday, March 13, 2006 10:53 AM Subject: [R] P-values i

[R] P-values in gls

2006-03-13 Thread Wilson, Andrew
When fitting a simple linear or polynomial regression using lm, R provides a p-value for the whole model as well as for the individual coefficients. When fitting the same models using gls (in order to correct for autocorrelation), there doesn't seem to be a p-value provided for the whole model, al

Re: [R] P-values from survreg (survival package) using a clusterterm

2006-03-06 Thread Peter Dalgaard
"Ladelund, Steen" <[EMAIL PROTECTED]> writes: > Hi all. > > Belove is the example from the cluster-help page wtih the output. > > I simply cannot figure out how to relate the estimate and robust Std. Err to > the p-value. I am aware this a marginal model applying the sandwich > estimator using (

[R] P-values from survreg (survival package) using a clusterterm

2006-03-06 Thread Ladelund, Steen
Hi all. Belove is the example from the cluster-help page wtih the output. I simply cannot figure out how to relate the estimate and robust Std. Err to the p-value. I am aware this a marginal model applying the sandwich estimator using (here I guess) an emperical (unstructered/exchangeable?) ICC.

Re: [R] p-values

2005-08-16 Thread Torsten Hothorn
On Thu, 4 Aug 2005, Peter Ho wrote: > HI R-users, > > I am trying to repeat an example from Rayner and Best "A contingency > table approach to nonparametric testing (Chapter 7, Ice cream example). > > In their book they calculate Durbin's statistic, D1, a dispersion > statistics, D2, and a residu

Re: [R] p-values

2005-08-11 Thread Peter Ho
Spencer, Here is an example from rayner and best 2001 and the script sent by Felipe. This can be done as follows using the function durbin.grupos() in the attached file > ###Ice cream example from Rayner and Best 2001 . Chapter 7 > judge <- rep(c(1:7),rep(3,7)) > variety <- c(1,2,4,2,3,5,3,4

Re: [R] p-values

2005-08-10 Thread Spencer Graves
pperm seems reasonable, though I have not looked at the details. We should be careful about terminology, however. So-called "exact p-values" are generally p-values computed assuming a distribution over a finite set of possible outcomes assuming some constraints to make the

Re: [R] p-values

2005-08-08 Thread Peter Ho
Spencer, Thank you for referring me to your other email on Exact goodness-of-fit test. However, I'm not entirely sure if what you mentioned is the same for my case. I'm not a statistician and it would help me if you could explain what you meant in a little more detail. Perhaps I need to expla

Re: [R] p-values

2005-08-06 Thread Spencer Graves
Hi, Peter: Please see my reply of a few minutes ago subject: exact goodness-of-fit test. I don't know Rayner and Best, but the same method, I think, should apply. spencer graves Peter Ho wrote: > HI R-users, > > I am trying to repeat an example from Rayner and Best "A contingency

[R] p-values

2005-08-04 Thread Peter Ho
HI R-users, I am trying to repeat an example from Rayner and Best "A contingency table approach to nonparametric testing (Chapter 7, Ice cream example). In their book they calculate Durbin's statistic, D1, a dispersion statistics, D2, and a residual. P-values for each statistic is calculated f

Re: [R] p-values for classification

2005-07-01 Thread Prof Brian Ripley
Not really an R question. Most classifiers will produce predicted probabilities, and you can check their accuracy. There are lots of details in my PRNN book, and some examples in MASS4. I suggest you adjust your training and test sets to be more nearly equal, or use cross-validation. I don't

[R] p-values for classification

2005-07-01 Thread Arne.Muller
Dear All, I'm classifying some data with various methods (binary classification). I'm interpreting the results via a confusion matrix from which I calculate the sensitifity and the fdr. The classifiers are trained on 575 data points and my test set has 50 data points. I'd like to calculate p-v

Re: [R] p values when using rlm

2005-03-26 Thread Marc Schwartz
On Sat, 2005-03-26 at 20:36 -0500, John Sorkin wrote: > R 2.0.1 > Linux > > I am using rlm() to fit a model, e.g. fit1<-rlm(y~x). My model is more > complex than the one shown. > > When I enter summary(fit1) > I get estimates for the model's coefficients along with their SEs, and > t values, b

[R] p values when using rlm

2005-03-26 Thread John Sorkin
R 2.0.1 Linux I am using rlm() to fit a model, e.g. fit1<-rlm(y~x). My model is more complex than the one shown. When I enter summary(fit1) I get estimates for the model's coefficients along with their SEs, and t values, but no p values. The p value column is blank. Similarly, when I enter ano

Re: [R] p-values for the dip test

2004-10-22 Thread Martin Maechler
Hmm, this is rather about reading the (Hartigan)^2 paper ... > "Kylie" == Kylie Lange <[EMAIL PROTECTED]> > on Fri, 22 Oct 2004 11:17:34 +0930 writes: Kylie> Hi all, Kylie> I am using Hartigan & Hartigan's [1] "dip test" of Kylie> unimodality via the diptest package in R.

[R] p-values for the dip test

2004-10-21 Thread Kylie Lange
Hi all, I am using Hartigan & Hartigan's [1] "dip test" of unimodality via the diptest package in R. The function dip() returns the value of the test statistic but I am having problems calculating the p-value associated with that value. I'm hoping someone here is familiar with this process and c

Re: [R] p-values

2004-05-02 Thread John Maindonald
Frank - Thanks for your reply, on which I really have no comment. There are contexts where a Bayesian approach necessary, natural and easy to handle, and can be used to broaden the inferential vision of students. Examples from HIV testing and mammography screening in Gigerenzer's book, sold in the

Re: [R] p-values

2004-05-02 Thread Frank E Harrell Jr
On Thu, 29 Apr 2004 14:49:26 +1000 John Maindonald <[EMAIL PROTECTED]> wrote: > This is, of course, not strictly about R. But if there should be > a decision to pursue such matters on this list, then we'd need > another list to which such discussion might be diverted. > > I've pulled Frank's "Re

RE: [R] p-values

2004-04-29 Thread Lucke, Joseph F
day, April 29, 2004 10:39 AM To: Thomas Lumley Cc: [EMAIL PROTECTED]; John Maindonald Subject: Re:[R] p-values On 29-Apr-04 Thomas Lumley wrote: > On Thu, 29 Apr 2004, John Maindonald wrote: > >> This is, of course, not strictly about R. But if there should be >> a decision to

Re:[R] p-values

2004-04-29 Thread Ted Harding
On 29-Apr-04 Thomas Lumley wrote: > On Thu, 29 Apr 2004, John Maindonald wrote: > >> This is, of course, not strictly about R. But if there should be >> a decision to pursue such matters on this list, then we'd need >> another list to which such discussion might be diverted. >> > > Ted Harding s

Re:[R] p-values

2004-04-29 Thread Thomas Lumley
On Thu, 29 Apr 2004, John Maindonald wrote: > This is, of course, not strictly about R. But if there should be > a decision to pursue such matters on this list, then we'd need > another list to which such discussion might be diverted. > Ted Harding started such a list (stats-discuss) quite some

Re:[R] p-values

2004-04-29 Thread partha_bagchi
ill have a section in his book in the future? John Maindonald <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED] 04/29/2004 12:49 AM To: [EMAIL PROTECTED] cc: [EMAIL PROTECTED], [EMAIL PROTECTED] Subject: Re:[R] p-values This is, of course, not strict

Re:[R] p-values

2004-04-29 Thread Ted Harding
On 29-Apr-04 John Maindonald wrote: > This is, of course, not strictly about R. But if there should be > a decision to pursue such matters on this list, then we'd need > another list to which such discussion might be diverted. A few of us have taken further discussion on this topic off-list, betw

Re:[R] p-values

2004-04-28 Thread John Maindonald
This is, of course, not strictly about R. But if there should be a decision to pursue such matters on this list, then we'd need another list to which such discussion might be diverted. I've pulled Frank's "Regression Modeling Stratregies" down from my shelf and looked to see what he says about inf

Re: [R] p-values

2004-04-28 Thread Frank E Harrell Jr
On Tue, 27 Apr 2004 22:25:22 +0100 (BST) (Ted Harding) <[EMAIL PROTECTED]> wrote: > On 27-Apr-04 Greg Tarpinian wrote: > > I apologize if this question is not completely > > appropriate for this list. > > Never mind! (I'm only hoping that my response is ... ) > > > [...] > > This week I have be

[R] p-values

2004-04-28 Thread John Maindonald
vity of results to the choice of prior? John Maindonald. From: Greg Tarpinian <[EMAIL PROTECTED]> Date: 28 April 2004 6:32:06 AM To: [EMAIL PROTECTED] Subject: [R] p-values I apologize if this question is not completely appropriate for this list. I have been using SAS for a while and am now in th

[R] P-values in ncf package

2003-10-29 Thread Rene Eschen
Group, I'm currently trying to find out how the function correlog in the ncf package may be useful to me for calculating cross-correlograms. The function's output includes P-values for all distance classes, but it seems that only positive values can become significant. Is this true and correct? If