Displaying 20 results from an estimated 400 matches similar to: "the sample() function"
2010 Oct 17
2
dpois().......bizarre warning messages
Dear Masters,
I have a question to submit
consider the following script
m<-4.95
obs<-rpois(36,m) # i generate 36 realization from a poisson(m)
hist(obs,freq=F)
curve(dpois(x,m),add=T,col="red") #i wish to overlay on the histogram the
theorical poisson density function
errors are returned saing the x vector doesn't contain integers....
really bizarre i can't give
2011 Jan 14
4
piecewise regression
Hello everybody!!!!
Quick question, if you'd like to throw a little tip:
does anyone knows a function that runs piecewise regression models with
coefficients estimation and inferences ?
Thank you
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2011 Jan 16
3
ODD ODD ODD stuff!!
Egregious,
look what just happened few minutes ago while opening up my program and
running the scripts
> A<-read.table("C:\\Documents and Settings\\
+ me\\Desktop\\TESI\\generale.txt",head=T)
Errore: non trovo la funzione "read.table" #CAN'T FIND read.table
FUNTION!!!??? ARE WE ok???
>
> B<-read.table("C:\\Documents and Settings\\
+
2011 Feb 08
3
intervals {nlme} lower CI greater than upper CI !!!????
Hi folks...
check this out..
> GLU<-lme(gluc~rt*cd4+sex+age+rf+nadir+pharmac+factor(hcv)+factor(hbs)+
+ haartd+hivdur+factor(arv),
+ random= ~rt|id, na.action=na.omit)
> intervals(GLU)$fixed
lower est. upper
(Intercept) 67.3467070345 7.362307e+01 7.989944e+01
rt *0.0148050160* 6.249304e-02 1.101811e-01
cd4
2011 Mar 18
1
PREDICTIONS from a PIECEWISE LINEAR (mixed) MODEL: THEY AIN'T LINEAR BETWEEN BREAK POINTS!!
I Dears,
if that wouldn't take u too much effort I'd like to ask for a swift opinion:
I have a alinear (mixed effect) model that I wish to run as a piecewise one.
When I predict the values Iget quite some odds and disturbing results:
The predicted stright line after the break point is not straight at all,
instead behaves like if it was a hig order polynomial or something
similar!!!!
I
2011 Jan 21
1
TRADUCING lmer() syntax into lme()
---------- Forwarded message ----------
From: Freddy Gamma <freddy.gamma@gmail.com>
Date: 2011/1/21
Subject: TRADUCING lmer() syntax into lme()
To: r-sig-mixed-models@r-project.org
Dear Rsociety,
I'd like to kingly ask to anyone is willing to answer me how to implement a
NON NESTED random effects structure in lme()
In particular I've tried the following translation from lmer to
2011 Jan 12
1
graphics: 3D regression plane
Hello Masters,
wishing you all a great 2011 I was also going to ask if anyone knows a quick
and efficient way to plot a regression plane (z~x*y).
I have tried the regr2.plot{HH} function but it is only an educational tool
and has poor graphical properties.
I also tried to run the following script on a fictitious longitudinal
problem, with poor results
set.seed(1234)
2010 Dec 29
1
logistic regression with response 0,1
Dear Masters,
first I'd like to wish u all a great 2011 and happy holydays by now,
second (here it come the boring stuff) I have a question to which I hope u
would answer:
I run a logistic regression by glm(), on the following data type
(y1=1,x1=x1); (y2=0,x2=x2);......(yn=0,xn=xn), where the response (y) is
abinary outcome on 0,1 amd x is any explanatory variable (continuous or not)
2010 Oct 26
2
anomalies with the loess() function
Hello Masters,
I run the loess() function to obtain local weighted regressions, given
lowess() can't handle NAs, but I don't
improve significantly my situation......, actually loess() performance leave
me much puzzled....
I attach my easy experiment below
#------SCRIPT----------------------------------------------
#I explore the functionalities of lowess() & loess()
#because I have
2017 Aug 17
2
PAM Clustering
Dear Germano,
Thank you for your fast reply,
In the above code, *MYData *is the actual data set.
Do not we need to convert *MYData to *the dissimilarity matrix using
*pam(as.dist(**MYData**), k = 10, diss = TRUE*)* code line?*
*Regards.*
On Thu, Aug 17, 2017 at 2:58 PM, Germano Rossi <germano.rossi at gmail.com>
wrote:
> try this
>
> MYdata <-
2011 Mar 19
1
strange PREDICTIONS from a PIECEWISE LINEAR (mixed) MODEL
Hi Dears,
When I introduce an interaciton in a piecewise model I obtain some quite
unusual results.
If that would't take u such a problem I'd really appreciate an advise from
you.
I've reproduced an example below...
Many thanks
x<-rnorm(1000)
y<-exp(-x)+rnorm(1000)
plot(x,y)
abline(v=-1,col=2,lty=2)
mod<-lm(y~x+x*(x>-1))
summary(mod)
yy<-predict(mod)
2009 May 21
2
Matrix sum
Someone knows the existence of a function to sum the elements of the same
place A[i,j] B[i,j] of a matrix?thank you
--
Dr. Daniele Riggi, PhD student
University of Milano-Bicocca
Department of Statistics
Building U7, Via Bicocca degli Arcimboldi, 8
20126 Milano, Italy
cell. +39 328 3380690
mailto: daniele.riggi@gmail.com
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2009 May 21
1
Rpart - best split selection for class method and Gini splitting index
Dear R-users,
I'm working with the Rpart package and trying to understand how the
procedure select the best split in the case the method "class" and the
splitting index "Gini" are used. In particular I'd like to have look to the
source code that works out the best split for un unordered predictor.
Does anyone can suggest me which functions in the sources I should
2009 May 21
1
em algorithm mixture of multivariate normals
Hi,
I would like to know if it is possible to have a "R code" to estimate the
parameters of a mixture of bivariate (or multivariate) normals via EM
Algorithm. I tried to write it, but in the estimation of the matrix of
variance and covariance, i have some problems. I generate two bidimensional
vectors both from different distribution with their own vector means and
variance and
2009 Jun 03
2
problem with uniroot
Hi R-users,I'm trying to solve a non linear equation, to find the degrees of
freedom of a mixture of t student. I'm sure i wrote the minimization
equation in the right way, but when i try to run the EM algorithm to
estimate the parameters of the mixture, the following error will appear:
Error in uniroot(function(z) log(z/2) - digamma(z/2) + 1 - log((z + d)/2) +
:
f() values at end
2011 Apr 12
2
a question on the use of 'solve'
Dear R users,
I am in trouble using the function
solve(matrix)
in a loop.
When it happens that I have a singular matrix, I get an error message saying
so and the loop stops.
My question is if there in any way to keep on going in the loop.
Thank you in advance,
Laura
*---------------------------------------------------------*
Laura Antolini, PhD
Department of
2017 Aug 17
0
PAM Clustering
Sorry, I never use pam. In the help, you can see that pam require a
dataframe OR a dissimilarity matrix. If diss=FALSE then "euclidean" was use.So,
I interpret that a matrix of dissimilarity is generated automatically.
Problems may be in your data. Indeed
pam(ruspini, 4)$diss
write a dissimilaty matrix
while
pam(MYdata,10)$diss
wite NULL
2017-08-17 16:03 GMT+02:00 Sema Atasever
2017 Aug 17
2
PAM Clustering
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2006 Sep 19
1
help on dirichlet distribution
Dear Gregory R. Warnes,
I'm a phd student in statistics, at the University of Milano Bicocca.
I'm interested to the methods of estimate the parameters of the Dirichlet distribution.
Do you have implemented an algorithm in R?
If so, can you give me the script? or, in general, some helps?
Best Regards
Gianna
---------------------------------------------------------------
Gianna Monti
2002 May 13
1
Spatio-temporal analysis of homicide rates
Dear R-listers,
I would like to carry out a very basic descriptive analysis of homicides
rates in Italy, taking into account both the spatial dimension (103
provinces) and the temporal dimension (10 years), but no covariates. In
practice, what I would like to do is to describe spatio-temporal variation
of homicide rates, identifying those combinations of province-year where
the homicide rate