Displaying 20 results from an estimated 200 matches similar to: "testing coeficients of glm"
2012 Mar 15
1
eigenvalues of matrices of partial derivatives with ryacas
Hello,
I am trying to construct two matrices, F and V, composed of partial
derivatives and then find the eigenvalues of F*Inverse(V). I have the
following equations in ryacas notation:
> library(Ryacas)
> FIh <- Expr("betah*Sh*Iv")
> FIv <- Expr("betav*Sv*Ih")
> VIh <- Expr("(muh + gamma)*Ih")
> VIv <- Expr("muv*Iv")
I
2008 Feb 15
1
Questions about EM algorithm
Dear all:
Assume I have 3 distributions, x1, x2, and x3.
x1 ~ normal(mu1, sd1)
x2 ~ normal(mu2, sd2)
x3 ~ normal(mu3, sd3)
y1 = x1 + x2
y2 = x1 + x3
Now that the data I can observed is only y1 and y2. It is
easy to estimate (mu1+m2), (mu1+mu3), (sd1^2+sd2^2) and
(sd1^2+sd3^2) by EM algorithm since
y1 ~ normal(mu1+mu2, sqrt(sd1^2+sd2^2)) and
y2 ~ normal(mu1+mu3, sqrt(sd1^2+sd3^2))
However, I want
2010 Mar 20
2
EM algorithm in R
Please help me in writing the R code for this problem. I've been solving this
for 4 days. It was hard for me to solve it. It's a simulation problem in R.
The problem is
My true model is a normal mixture which is given as
0.5 N(-0.8,1) + 0.5 N(0.8,1). This model has two components.
I will get a random sample of size 100 from this model. I will do this 300
times.
That means, I will have
2006 May 21
2
nls & fitting
Dear All,
I may look ridiculous, but I am puzzled at the behavior of the nls with
a fitting I am currently dealing with.
My data are:
x N
1 346.4102 145.428256
2 447.2136 169.530634
3 570.0877 144.081627
4 721.1103 106.363316
5 894.4272 130.390552
6 1264.9111 36.727069
7 1788.8544 52.848587
8 2449.4897 25.128742
9 3464.1016 7.531766
10 4472.1360 8.827367
11
2008 Apr 05
2
How to improve the "OPTIM" results
Dear R users,
I used to "OPTIM" to minimize the obj. function below. Even though I used
the true parameter values as initial values, the results are not very good.
How could I improve my results? Any suggestion will be greatly appreciated.
Regards,
Kathryn Lord
#------------------------------------------------------------------------------------------
x = c(0.35938587,
2008 Apr 05
2
How to improve the "OPTIM" results
Dear R users,
I used to "OPTIM" to minimize the obj. function below. Even though I used
the true parameter values as initial values, the results are not very good.
How could I improve my results? Any suggestion will be greatly appreciated.
Regards,
Kathryn Lord
#------------------------------------------------------------------------------------------
x = c(0.35938587,
2010 Jun 13
1
using latticeExtra plotting confidence intervals
I am wanting to plot a 95% confidence band using segplot, yet I am wanting
to have groups. For example if I have males and females, and then I have
them in different races, I want the racial groups in different panels. I
have this minor code, completely made up but gets at what I am wanting, 4
random samples and 4 samples of confidence, I know how to get A & B into one
panel and C&D in to
2004 Nov 08
1
plotting lm coeficients with their means
I am trying to write a function that will run a linear
model and plot the regression coeficients with their
corresponding means. I am having two problems. I can
get the plot with the function below, but I am having
trouble labeling the points.
function(y,x1,x2,x3,x4){
outlm<-lm(y~x1+x2+x3+x4)
imp<-as.data.frame(outlm$coef[-1])
meanvec<-c(mean(x1),mean(x2),mean(x3),mean(x4))
2009 Oct 31
1
Help me improving my code
Hi,
I am new to R. My problem is with the ordered logistic model. Here is my
question:
Generate an order discrete variable using the variable
wrwage1 = wages in first full calendar quarter after benefit application
in the following way:
*
wage*1*Ordered *=
1 *if*0 *· wrwage*1 *< *1000
2 *if*1000 *· wrwage*1 *< *2000
3 *if*2000 *· wrwage*1 *< *3000
4 *if*3000 *· wrwage*1 *<
2013 May 08
1
How to calculate Hightest Posterior Density (HPD) of coeficients in a simple regression (lm) in R?
Hi!
I am trying to calculate HPD for the coeficients of regression models
fitted with lm or lmrob in R, pretty much in the same way that can be
accomplished by the association of mcmcsamp and HPDinterval functions for
multilevel models fitted with lmer. Can anyone point me in the right
direction on which packages/how to implement this?
Thanks for your time!
R.
[[alternative HTML version
2009 Sep 26
1
renaming intercept column when retrieving coeficients from lme using coef function
I am still fairly new to R and have a fairly rudimentary question. I am
trying to name a vector of coefficients retrieved from a multilevel model
using the coef function. I guess the default name is "Intercept" and I
cannot figure out how to rename it.
I have tried the using the code below to name the column of coefficients
ind.y derived from an lme model. Unfortunately, the
2017 Dec 06
2
Coeficients estimation in a repeated measures linear model
Dear Users,
I am trying to understand the inner workings of a repeated measures linear
model. Take for example a situation with 6 individuals sampled twice for
two conditions (control and treated).
set.seed(12)
ctrl <- rnorm(n = 6, mean = 2)
ttd <- rnorm(n = 6, mean = 10)
dat <- data.frame(vals = c(ctrl, ttd),
group = c(rep("ctrl", 6), rep("ttd",
2003 Jun 25
2
within group variance of the coeficients in LME
Dear listers,
I can't find the variance or se of the coefficients in a multilevel model
using lme.
I want to calculate a Chi square test statistics for the variability of the
coefficients across levels. I have a simple 2-level problem, where I want to
check weather a certain covariate varies across level 2 units. Pinheiro
Bates suggest just looking at the intervals or doing a rather
2010 Jul 18
2
loop troubles
Hi all, I appreciate the help this list has given me before. I have a
question which has been perplexing me. I have been working on doing a
Bayesian calculating inserting studies sequentially after using a
non-informative prior to get a meta-analysis type result. I created a
function using three iterations of this, my code is below. I insert prior
mean and precision (I add precision manually
2008 Jul 07
5
question on lm or glm matrix of coeficients X test data terms
Hi,
is there an easy way to get the calculated weights in a regression equation?
for e.g.
if my model has 2 variables 1 and 2 with coefficient .05 and .6
how can I get the computed values for a test dataset for each coefficient?
data
var1,var2
10,100
so I want to get .5, 60 back in a vector. This is a one row example but I would want to get a matrix of multiplied out coefficients
2008 Jul 28
1
Mixed model question.
I continue to struggle with mixed models. The square zero version
of the problem that I am trying to deal with is as follows:
A number (240) of students are measured (tested; for reading
comprehension)
on 6 separate occasions. Initially (square zero) I want to treat the
test time as a factor (with 6 levels). The students are of course
``random effects''. Later I want to look at
2001 Oct 22
1
basic question
hi there,
i'm about to install wine on my debian system. is it better to use libwine
for the dll's or is it better to use MS's dll's?
thanks,
pete
--
"You may not use the Software in connection with any site that disparages
Microsoft, MSN, MSNBC, Expedia, or their products or services ..."
-- Clause from license for FrontPage 2002
2001 Oct 25
1
basic install questions
Hello,
I was reading the docs and have a few questions:
1. I compile wine from the daily debian repository at gluck.debian.org.
Do I still need to first remove the old wine before dpkg'ing a newly
compiled wine source?
2. I plan on installing wine WITH Windows. Can I still use winesetuptk?
I can ignore installation on wine-lib, right?
3. Copyright issues aside, would the most
2009 Aug 31
4
Book on R programming
Most books on R I come across describe running statistical procedures in R.
Any suggestions on a good book that teaches *programming* in R?
Thanks,
Anjan
--
=============================
anjan purkayastha, phd
bioinformatics analyst
whitehead institute for biomedical research
nine cambridge center
cambridge, ma 02142
purkayas [at] wi [dot] mit [dot] edu
703.740.6939
[[alternative HTML version
2008 Dec 08
1
Multivariate kernel density estimation
I would like to estimate a 95% highest density area for a multivariate
parameter space (In the context of anova). Unfortunately I have only
experience with univariate kernel density estimation, which is remarkebly
easier :)
Using Gibbs, i have sampled from a posterior distirbution of an Anova model
with k means (mu) and 1 common residual variance (s2). The means are
independent of eachother, but