Displaying 20 results from an estimated 143 matches for "lm1".
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2013 Mar 18
1
try/tryCatch
...e", "spec_se")
k=1
for(ii in 1:dim(mydata)[3]){
tmp<-mydata[,,ii]
tmp1<-as.data.frame(tmp)
names(tmp1)=c("persons", "d1", "tp", "fn", "fp", "fn", "detect", "d0",
"outcome")
lm1<-try(lmer(outcome~0+d1+d0+(0+d1+d0 | persons), family=binomial,
data=tmp1, nAGQ=3), silent=T)
if(class(lm1)[1]!='try-error'){
a[ii,1]=lm1@fixef[1]
a[ii,2]=lm1@fixef[2]
a[ii,3]=vcov(lm1)[1,2]/prod(sqrt(diag(vcov(lm1))))
a[ii,4:5]=sqrt(diag(vcov(lm1)))...
2003 Jul 30
2
Comparing two regression slopes
...oncerned,
because when I test it on simulated data with different sample sizes and
variances, the function seems to be extremely sensitive both of these. I am
wondering if I've missed something in my function? I'd be very grateful for
any tips.
Thanks!
Martin
TwoSlope <-function(lm1, lm2) {
## lm1 and lm2 are two linear models on independent data sets
coef1 <-summary(lm1)$coef
coef2 <-summary(lm2)$coef
sigma <-(sum(lm1$residuals^2)+sum(lm2$residuals^2))/(lm1$df.residual +
lm2$df.residual-4)
SSall <-sum(lm1$model[,2]^2) + sum(lm2$model[,2]^2)
SSprod <-sum(lm1...
2005 Mar 09
1
multiple comparisons for lme using multcomp
...Al800 q 1.0
69 Al800 r 0.8
70 Al800 r 0.9
71 Al800 r 0.9
72 Al800 r 0.6
73 Al800 s 0.9
74 Al800 s 1.0
75 Al800 s 0.8
76 Al800 s 0.8
77 Al800 s 0.7
> attach(tab)
> library(nlme)
> lm1<-lme(response~treatment,random=~1|box)
> library(multcomp)
Loading required package: mvtnorm
> # first way to do (seem uncorrect)
> summary(csimtest(coef(lm1),vcov(lm1),cmatrix=contrMat(table(treatment),
type="Tukey"),df=59))
Error in csimtest(coef(lm1), vcov(lm1), cmatrix...
2006 May 06
2
How to test for significance of random effects?
...me() does provide a confidence interval for the between-group variance,
but this is constructed so as to never include zero (I guess the interval
is as narrow as possible on log scale, or something). I would be grateful
if anyone could tell me how to test for zero variance between groups.
If lm1 and lme1 are fitted with lm() and lme() respectively, then
anova(lm1,lme1) gives an error, whereas anova(lme1,lm1) gives an answer
which looks reasonable enough.
The command logLik() can retrieve either restricted or ordinary
log-likelihoods from a fitted model object, but the likelihoods ar...
2005 May 31
2
simple predict question
Excuse the simple question...
I'm not sure what I'm doing wrong with predict, but let me use this example:
Suppose I do:
dat<-matrix(c(0,0,10,20),2,byrow=T)
lm1<-lm(dat[,2]~dat[,1])
Suppose I want to generate the linearly-interpolated y-values between the
point (0,0) and (0,20) at every unit interval.
I thought I just do:
predict(lm1, data.frame(seq(0,10,1))) to get 0,2,4,6...,18,20, but instead
I just get:
1 2
0 20
Any suggestions?
Thanks,
Ste...
2006 Nov 30
1
data.frame within a function (PR#9294) (cont'd)
...k\n")
}
#########################
# compare f1() and f2() #
#########################
f1<- function(){
x<- rnorm(10)
y<- rmvnorm(10,mean=c(1,2)); colnames(y)<- paste("y",1:2,sep="")
#c("y1","y2")
dtf<- data.frame(y,x)
lm1<- lm(cbind(y1,y2)~1,data=dtf); cat("ok\n")
update(lm1,~ .+x,evaluate=T); cat("also ok\n") # only this line is
different
}
f2<- function(){
x<- rnorm(10)
y<- rmvnorm(10,mean=c(1,2)); colnames(y)<- paste("y",1:2,sep="")
#c(&...
2008 Sep 17
2
Command Prompt Question
...: if I enter example(AIC), instead of just getting the
regular '>' before each output line, I get 'AIC>' instead. I only want
the '>' and have searched everywhere and can't find an option to change
this.
Thanks
David
-----------------------
AIC> lm1 <- lm(Fertility ~ . , data = swiss)
AIC> AIC(lm1)
[1] 326.0716
AIC> stopifnot(all.equal(AIC(lm1),
AIC+ AIC(logLik(lm1))))
AIC> ## a version of BIC or Schwarz' BC :
AIC> AIC(lm1, k = log(nrow(swiss)))
[1] 339.0226
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2010 Aug 17
2
how to selection model by BIC
Hi All:
the package "MuMIn" can be used to select the model based on AIC or AICc.
The code is as follows:
data(Cement)
lm1 <- lm(y ~ ., data = Cement)
dd <- dredge(lm1,rank="AIC")
print(dd)
If I want to select the model by BIC, what code do I need to use? And when
to select the best model based on AIC, what the differences between the
function "dredge" in package"MuMIn" and the fun...
2013 May 01
2
significantly different from one (not zero) using lm
Hello,
I am work with a linear regression model:
y=ax+b with the function of lm.
y= observed migration distance of butterflies
x= predicted migration distance of butterflies
Usually the result will show
if the linear term a is significantly different from zero based on the
p-value.
Now I would like to test if the linear term is significantly different from
one.
(because I want to know
2006 Apr 14
5
vector-factor operation
I found myself wanting to average a vector [vec] within each level of a
factor [Fac], returning a vector of the same length as vec. After a
while I realised that
lm1 <- lm(vec ~ Fac)
fitted(lm1)
did what I want.
But there must be another way to do this, and it would be good to be
able to apply other functions than mean() in this way.
Cheers, Murray
--
Dr Murray Jorgensen http://www.stats.waikato.ac.nz/Staff/maj.html
Department of Statistics, Univer...
2012 May 22
1
Adding Text to a Plot
Hi, all!
I'm pretty sure I'm missing something about this.
Is there a smart way of typping hat(R)^2 and it's value from a linear
regression?
I've just found this tricky one:
# Sample data
x <- sample(1:100,10)
y <- 2+3*x+rnorm(10)
# Run the regression
lm1 <- lm(y~x)
# Plotting
plot(x,y, main="Linear Regression", col="red")
abline(lm1, col="blue")
placex <- par("usr")[1]+.1*(par("usr")[2]-par("usr")[1])
placey1 <- par("usr")[3]+.9*(par("usr")[4]-par(&q...
2006 Jun 07
4
R crashes on quantreg
I was trying "quantreg" package,
lm1 <- lm(y~x)
rq1 <- rq(y~x)
plot(summary(rq1)) #then got a warning says singular value, etc. but this
line can be omited
plot(lm1) #crash here
It happened every time on my PC, Windows XP Pro Serv. Pack 1, Pentium(4)
3.00G.
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2013 Jan 18
1
Object created within a function disappears after the function is run
...traitsclean<-traits
birdhabitat<-merge(birdmatrix,habitatmatrix,by="SARBASINYEAR") #merge bird
and habitat data
data<-birdhabitat; data$SAR<-substr(data$SARBASINYEAR,1,3) #convenience;
create SAR variable
#make a FUNCTION to combine variables into models
dredgeit<-function(lm1){
dd1<-dredge(lm1,eval=FALSE) #create all possible combinations
dd1<-gsub("formula = ","",dd1,fixed=TRUE) #delete characters
dd1<-gsub(" + 1","",dd1,fixed=TRUE) #delete characters
dd1#inspect model formulae
}
lm1<-lm(data$BiRich.o~log(data$HaArea...
2012 May 27
7
Customized R Regression Output?
Hello R-Experts,
I am facing the problem that I have to estimate several parameters for a lot
of different dependent variables.
One single regression looks something like this:
y = beta0 + beta1 * x1 + beta2 * x2 + beta3 * x1 * x2 + beta4 * x4 + beta5 *
lag(x4,-1)
where y is the dependent variable and xi are the independent ones. Important
to me are the different estimates of betai and their
2010 Jun 17
1
Problems using allEffects() (package effect)
...14.03
55805.1 55805 7 3 3 1 59.92
55829.1 55829 7 3 1 1 15.31
55806.1 55806 7 3 2 1 28.01
50725.1 50725 7 3 2 1 34.48
55737.1 55737 7 3 2 1 43.56
The linear model is also quite simple :
> lm1=lm(Volume ~ temps + Traitement:temps + S?rie , data)
But when I try to use allEffects() I get this error:
> eff.lm1 <- allEffect(mod=lm1,
Error in apply(mod.matrix[, components], 1, prod) : index out of range
I read the help and the example but I don't understand the reason why it
does...
2010 Oct 12
1
delta AIC for models with 2 variables using MuMIn
...f it is possible to show models
with any two only certain variables.
Thank you.
Elaine
I asked a similar question and got a great help for models
with only one variable as below.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In effect, you want
data(Cement)
lm1 <- lm(y ~ ., data = Cement)
dd <- dredge(lm1, subset = X1)
want <- with(dd, is.na(X) & is.na(X2) & is.na(X3) & is.na(X4))
want
## how many models selected?
sum(want)
## OK selected just 1, show it
dd[want, , drop = FALSE]
Oh, actually, I suppose you could automate this, so it...
2009 Jan 16
1
specifying model terms when using predict
...ould be acceptable in all situations but it seems models
written this way are not accepted by the predict function. Perhaps
others have encountered this problem as well.
The code below illustrates the issue.
######
## linear model example
# this works
x<-1:100
y<-2*x
lm1<-glm(y~x)
pred1<-predict(lm1,newdata=data.frame(x=101:150))
## so does this
x<-1:100
y<-2*x
orig.df<-data.frame(x1=x,y1=y)
lm1<-glm(y1~x1,data=orig.df)
pred1<-predict(lm1,newdata=data.frame(x1=101:150))
## this does not run
x<-1:100
y<-2*x
ori...
2010 Apr 08
2
Overfitting/Calibration plots (Statistics question)
...f the data:
> x1 <- rnorm(200, 0, 1)
> x2 <- rnorm(200, 0, 1)
> x3 <- rnorm(200, 0, 1)
> x4 <- rnorm(200, 0, 1)
> x5 <- rnorm(200, 0, 1)
> x6 <- rnorm(200, 0, 1)
> y <- x1 + x2 + rnorm(200, 0, 2)
> d <- data.frame(y, x1, x2, x3, x4, x5, x6)
>
> lm1 <- lm(y ~ ., data = d[1:100,])
> lm2 <- lm(y ~ x1 + x2, data = d[1:100,])
>
> plot(predict(lm1, d[101:200, ]), d$y[101:200]); abline(0,1)
> x11(); plot(predict(lm2, d[101:200, ]), d$y[101:200]); abline(0,1)
The plots for both lm1 and lm2 show the points scattered around a line
wi...
2007 Apr 02
2
Why does lmList() fail when lm() doesn't?
Dear r-helpers,
Can anyone suggest why lm() doesn't complain here:
summary(osss.lm1 <- lm(logOdds ~ c.setSize %in% task, data = osss))
whereas in package:nlme (and in package:lme4)
osss.lmL <- lmList(logOdds ~ c.setSize %in% task | subj, data = osss)
# Error in `contrasts<-`(`*tmp*`, value = "contr.treatment") :
# contrasts can be applied only to factors with...
2014 Jun 24
2
Making several plots using a loop function
...rent plots.
Specifically, for the code below, I generated 9 plots. I would like to add
a title to each plot.
For example, the titles will be respectively, plot1, plot 2, … plot 9.
Thank you very much!
Hanna
par(mfrow=c(3,3), pty="s", pch=16, col="blue")
for ( i in 1:9) {
lm1 <- lm(log(run_res[2:11, i]) ~ log(level))
plot(log(level), log(run_res[2:11, i]), xlab="dllution levels",
ylab="%PS-80")
abline(lm1)}
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