Displaying 20 results from an estimated 8000 matches similar to: "question about linear mixed model"
2011 Jun 28
1
About the covariant
Hi all,I have some questions about the covariants of regression.
My target: To explore the trend of CD4 level through a period of time.
Response variable: CD4 count
Explanatory variable:time
Also, the demology information is available,such as gender,occupation,income
level...
Q1,Are these variables of demology information called covariant?
Q2,How can I correct the impact of
2011 Jul 26
3
a question about glht function
Hi all:
There's a question about glht function.
My data:data_ori,which inclue CD4, GROUP,time.
f_GROUP<-factor(data_ori$GROUP)
f_GROUP is a factor of 3 levels(0,1,2,3)
result <- lme(sqrt(CD4) ~ f_GROUP*time ,random = ~time|ID,data=data_ori)
glht(result, linfct = mcp(f_GROUP="Tukey") )
Error in `[.data.frame`(mf, nhypo[checknm]) : undefined columns selected
I can't
2011 Feb 08
3
intervals {nlme} lower CI greater than upper CI !!!????
Hi folks...
check this out..
> GLU<-lme(gluc~rt*cd4+sex+age+rf+nadir+pharmac+factor(hcv)+factor(hbs)+
+ haartd+hivdur+factor(arv),
+ random= ~rt|id, na.action=na.omit)
> intervals(GLU)$fixed
lower est. upper
(Intercept) 67.3467070345 7.362307e+01 7.989944e+01
rt *0.0148050160* 6.249304e-02 1.101811e-01
cd4
2011 Feb 06
1
random interaction effect in lmer
Hi dears while modeling an interaction random effect in lmer i receive the
instantaneous error message
> ldlM4<-lmer(ldl~rt*cd4+age+rf+pharmac+factor(hcv)+
+ hivdur+(rt:cd4|id),na.action=na.omit,REML=F)
*Warning message:
In mer_finalize(ans) : false convergence (8)
*
I think the matter lies in syntax, 'cause i sistematically receive the same
message even when changing response...
PS:
2002 Sep 09
1
Plots by subject
Hello! I need some help with creating plots for each study subject. I have
tried the 'for' command as described in 'An Introduction to R', but I wasn't
successful.
Here's what I want to do:
-Create and save the following overlayed scatterplots for each subject (1 to
n).
-The data frame is in the form of one line per visit per subject (so more than
one line per
2011 Jul 25
1
lme convergence error
Hello, I am working from a linux 64 machine on a server with R-2.12 (I can't
update to 2.13). I am iterating through many linear mixed models for
longitudinal data and I occasionally receive the following convergence
error:
> BI.lme <- lme(cd4 ~ time + genBI + genBI:time + C1 + C2 + C11 + C12,
random =~ 1 + time | IID, data = d)
Error in lme.formula(cd4 ~ time + genBI + genBI:time +
2011 Dec 13
8
How to compute 95%CI for OR from logistic regression?
Hi all:
My data has 3 variables:
age(3levels : <30y=1 30-50y=2, >50y=3)
gender(Male=0, Female=1)
CD4 cell count(raw lab measurement)
y(1:death 0:alive)
I perform logistic regression to find out the factors that influence y.
result<-glm(y ~ factor(age) + factor(gender) + CD4,family = binomial)
>From the result,I can get OR(Odds Ratio) of gender via exp(Estimate of Female,
2011 Jul 02
0
The test of randomized slopes(intercepts)
Hi all:
I perform the linear mixed model for 300 persons, y is CD4 count,x is time.
I randomized slope and intercept,so I can get 300 slopes and 300 intercepts.Now I wanna test wheter the variance of 300 slopes and 300 intercepts differs from zero. If the variance of 300 slopes(or intercepts) differs from zero at 0.05 significant level,I should randomize the slope(or intercept), and if not,I
2009 Dec 29
2
pass functions and arguments to function
Hi,
I wonder how to pass several functions and their arguments as arguments to
a function. For example, the main function is
f = function(X ) {
process1(X)
...
process2(X)
}
I have a few functions that operate on X, e.g. g1(X, par1), g2(X, par2),
g3(X, par3). par1, par2 and par3 are parameters and of different types. I
would like to pass g1, g2, g3 and their arguments to f and g1,
2013 Jan 24
1
Pairwise Comparrisons
Dear all,
I''m trying to write a function, that will take as an argument, some aligned genome sequences, and using a sliding window, do pairwise comparisons of sequence similarity. Coding the sliding window I think I can manage but what I''m trying to get to grips with is getting it so as every pairwise comparison is made, no matter how many genomes are added, from 3 to N.
So if
2009 Jul 15
1
Help with averaging
Hi
I am using the following script to average a set of data 0f 62 columns into 31 colums. The data consists of values of ln(0.01) or -4.60517 instead of NA's. These need to be averaged for each row (i.e 2 values being averaged). What I would I need to change for me to meet the conditions:
1. If each run of the sample has a value, the average is
given
2. If only one run of the sample has a
2012 Jun 04
1
simulation of modified bartlett's test
Hi, I run this code to get the power of the test for modified bartlett's
test..but I'm not really sure that my coding is right..
#normal distribution unequal variance
asim<-5000
pv<-rep(NA,asim)
for(i in 1:asim)
{print(i)
set.seed(i)
n1<-20
n2<-20
n3<-20
mu<-0
sd1<-sqrt(25)
sd2<-sqrt(50)
sd3<-sqrt(100)
g1<-rnorm(n1,mu,sd1)
g2<-rnorm(n2,mu,sd2)
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,
2012 May 23
0
gam (mgcv) vs. multiple regression breakpoint analysis: inconsistencies?
Dear useRs,
I have a question with respect to fitting a non-linearity using gam
(mgcv package, version 1.7-16).
In a study I'm currently conducting, I'd like to find out if there is
a breakpoint after which the effect of Age of Acquisition (AOA) of the
second language changes. I.e. if the slope of AOA before the
breakpoint (at a certain AOA) is different from the slope past the
2024 Jul 25
1
please help generate a square correlation matrix
?s 17:39 de 25/07/2024, Yuan Chun Ding via R-help escreveu:
> Hi R users,
>
> I generated a square correlation matrix for the dat dataframe below;
> dat<-data.frame(g1=c(1,0,0,1,1,1,0,0,0),
> g2=c(0,1,0,1,0,1,1,0,0),
> g3=c(1,1,0,0,0,1,0,0,0),
> g4=c(0,1,0,1,1,1,1,1,0))
> library("Hmisc")
> dat.rcorr =
2011 Feb 18
3
How to change dataframe to tables
The data is in the attachment.
What I wanna get is:
, , Sex = Male
Eye
Hair Brown Blue Hazel Green
Black 32 11 10 3
Brown 53 50 25 15
Red 10 10 7 7
Blond 3 30 5 8
, , Sex = Female
Eye
Hair Brown Blue Hazel Green
Black 36 9 5 2
Brown 66 34 29 14
Red 16 7 7 7
Blond 4
2009 Apr 16
1
How can I catch errors thrown from c via the Rcpp error() function?
Hi
I am using the flowClust package from BioConductor, which is largely
implemented in c. For some of my data, the package occasionally (and
quite stochastically) encounters a particular condition which halts its
operation. At this point, it calls the error() function defined by Rcpp,
and halts.
What I would like to be able to do is to catch the error thrown, and
retry the operation a few
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
2024 Jul 25
1
please help generate a square correlation matrix
HI Rui,
Thank you for the help!
You did not remove a row if zero values exist in both column pair, right?
Ding
From: Rui Barradas <ruipbarradas at sapo.pt>
Sent: Thursday, July 25, 2024 11:15 AM
To: Yuan Chun Ding <ycding at coh.org>; r-help at r-project.org
Subject: Re: [R] please help generate a square correlation matrix
?s 17:?39 de 25/07/2024, Yuan Chun Ding via R-help