Displaying 20 results from an estimated 1000 matches similar to: "Problems getting slope and intercept to change when do multiple reps."
2012 Oct 20
1
Logistic regression/Cut point? predict ??
I am new to R and I am trying to do a monte carlo simulation where I
generate data and interject error then test various cut points; however, my
output was garbage (at x equal zero, I did not get .50)
I am basically testing the performance of classifiers.
Here is the code:
n <- 1000; # Sample size
fitglm <- function(sigma,tau){
x <- rnorm(n,0,sigma)
intercept <- 0
beta
2012 Oct 25
2
How to extract auc, specificity and sensitivity
I am running my code in a loop and it does not work but when I run it
outside the loop I get the values I want.
n <- 1000; # Sample size
fitglm <- function(sigma,tau){
x <- rnorm(n,0,sigma)
intercept <- 0
beta <- 0
ystar <- intercept+beta*x
z <- rbinom(n,1,plogis(ystar))
xerr <- x + rnorm(n,0,tau)
model<-glm(z ~ xerr, family=binomial(logit))
2001 Aug 30
1
MCMC coding problem
Dear All,
I am trying to convert some S-plus code that I have to run MCMC into
R-code. The program works in S-plus, but runs slowly.
I have managed to source the program into R. R recognizes that the program
is there; for example, it will display the code when I type the function
name at the prompt. However, the program will not run. When I try to run
the program, I get the following error
2011 Oct 28
4
Contrasts with an interaction. How does one specify the dummy variables for the interaction
Forgive my resending this post. To data I have received only one response (thank you Bert Gunter), and I still do not have an answer to my question.
Respectfully,
John
Windows XP
R 2.12.1
contrast package.
I am trying to understand how to create contrasts for a model that contatains an interaction. I can get contrasts to work for a model without interaction, but not after adding the
2008 Oct 01
0
xpred.rpart() in library(mvpart)
R-users
E-mail: r-help@r-project.org
Hi! R-users.
http://finzi.psych.upenn.edu/R/library/mvpart/html/xpred.rpart.html
says:
data(car.test.frame)
fit <- rpart(Mileage ~ Weight, car.test.frame)
xmat <- xpred.rpart(fit)
xerr <- (xmat - car.test.frame$Mileage)^2
apply(xerr, 2, sum) # cross-validated error estimate
# approx same result as rel. error from printcp(fit)
apply(xerr, 2,
2006 Jan 19
2
Tobit estimation?
Folks,
Based on
http://www.biostat.wustl.edu/archives/html/s-news/1999-06/msg00125.html
I thought I should experiment with using survreg() to estimate tobit
models.
I start by simulating a data frame with 100 observations from a tobit model
> x1 <- runif(100)
> x2 <- runif(100)*3
> ystar <- 2 + 3*x1 - 4*x2 + rnorm(100)*2
> y <- ystar
> censored <- ystar <= 0
2008 Sep 15
0
Simple censored quantile regression question
I start by doing a simple gaussian tobit by MLE:
x1 <- runif(1000) # E() = 0.5
x2 <- runif(1000)*2 # E() = 1
x3 <- runif(1000)*4 # E() = 2
ystar <- -7 + 4*x1 + 5*x2 + rnorm(1000) # is mean 0
y <- ystar
censored <- ystar <= 0
y[censored] <- 0
library(AER)
m <- tobit(y ~ x1 + x2, left=0, data=D)
summary(m)
Which gives:
Call:
2002 Feb 11
0
profile
I am running 1.3.1 on a Windows (NT 4.0) machine. I've fit a nonlinear
model intended to predict crop yield from nutrient information, and want to
use the profile function. If I type say,
profile(simparj.fm)
I get the following error message:
"Error in prof$getProfile(): number of iterations exceeded maximum of
5.25515e-308"
I used the profiler function to profile simparj,fm step
2018 Jan 20
1
Specification: Bi variate minimization problem
------------------- Version 2 of my problem improving the definition of what the optimal solution would be.
Dear all,
I'm working on the following problem:
Assume two datasets: Y, Y that represent the same physical quantity Q. Dataset X contains values of Q after an event A while dataset Y contains values of Q after an event B.
In R X, Y are vectors of the same length, containing
2009 Apr 23
2
Two 3D cones in one graph
Dear R-users:
The following code produces two cones in two panels. What I would like
to have is to have them in one, and to meet in the origin. Does anyone
have any good ideas how to do this?
Thanks for your help
Jaakko
library(lattice)
A<-matrix(ncol=2, nrow=64)
for(i in 0:63)
{
A[i+1,1]<-sin(i/10)
A[i+1,2]<-cos(i/10)
}
2015 Jul 02
0
[PATCH] Fix various -Wformat problems.
Updating gnulib has caused -Wformat-signedness to be enabled. This
has revealed many problems in C format strings. The fixes here fall
into the following main categories:
- Using %d with an unsigned parameter.
- %x and %o expect an unsigned argument.
- uid_t and gid_t are unsigned on Linux. The safe way to print these
is to cast them to uintmax_t and then print then using the %ju
2015 Jul 02
0
[PATCH v2] Fix various -Wformat problems.
Updating gnulib has caused -Wformat-signedness to be enabled. This
has revealed many problems in C format strings. The fixes here fall
into the following main categories:
- Using %d with an unsigned parameter.
- %x and %o expect an unsigned argument.
- uid_t and gid_t are unsigned on Linux. The safe way to print these
is to cast them to uintmax_t and then print them using the %ju
2008 Dec 09
1
glm error message when using family Gamma(link="inverse")
R 2.5
windows XP
I am getting an error from glm() that I don't understand. Any help or suggestions would be appreciated. N.B. 1<=AAMTCAREJ<=327900
> summary(data$AAMTCAREJ)
Min. 1st Qu. Median Mean 3rd Qu. Max.
1.0 404.3 1430.0 6567.0 5457.0 327900.0
> fitglm<-glm(AAMTCAREJ~sexcat+H_AGE+SmokeCat+InsuranceCat+MedicadeCat+
+
2017 Aug 09
0
Random slope random intercept plot after clmm regression
0down votefavorite
<https://stats.stackexchange.com/questions/296569/how-to-obtain-random-slope-random-intercept-plots-for-categorical-response-varia#>
I'm trying to generate a random slope random intercept plot after ordinal
regression using the clmmfunction from the ordinal package in R. I have
aggression levels which are categorical with six levels. Earlier, I made
random intercept
2007 Dec 02
0
error messgage in lmer for random intercept and slope model
Greetings,
I am trying to run a logistic regression model for binary data with a random
intercept and slope in R 2.6.1. When I use the code:
lmer1<-lmer(infect ~ time+gender + (1+time|id), family=binomial, data=ichs,
method="Laplace")
Then from:
summary(lmer1)
I get the message:
Error in if (any(sd < 0)) return("'sd' slot has negative entries") :
missing
2012 Apr 05
0
Normalizing linear regression slope to intercept
I am wondering if it possible to normalize the slope of a linear regression to its intercept to allow for valid between-group comparisons.
Here is the scenario:
I need to compare the slopes of biomass increase among NAFO divisions of Northwest Atlantic cod. However, the initial division biomass is a confounding factor that may influence the slope of the regression model. How can I normalize the
2010 Sep 10
1
lme, groupedData, random intercept and slope
Windows Vista
R 2.10.1
Does the following use of groupedData and lme produce an analysis with both random intercept and slope, or only random slope?
zz<-groupedData(y~time | Subject,data=data.frame(data),
labels = list( x = "Time",
y = "y" ),
units = list( x = "(yr)", y = "(mm)")
)
plot(zz)
2013 Oct 26
2
Problems with lme random slope+intercept model
Dear all,
I'm trying to fit a model on ecological data in which I have measured a few
biotic and abiotic factors over the course of a few days in several
individuals. Specifically, I'm interested in modelling y ~ x1, with x2, x3,
and 'factor' as independent variables. Because data suggests both slope and
intercept (for y ~x1) might differ between individuals, I'd want to
2008 Dec 16
1
Prediction intervals for zero inflated Poisson regression
Dear all,
I'm using zeroinfl() from the pscl-package for zero inflated Poisson
regression. I would like to calculate (aproximate) prediction intervals
for the fitted values. The package itself does not provide them. Can
this be calculated analyticaly? Or do I have to use bootstrap?
What I tried until now is to use bootstrap to estimate these intervals.
Any comments on the code are welcome.
2006 Oct 30
1
Random intercept-slope correlation (nlme)
Dear list members,
I am working with a multilevel growth curve, that in its simplest form goes
like follows:
Yit = Ai + Bi t + eit (the error term is assumed to follow an AR(1)
autorregressive process)
One major topic in my research is the convergence in the values of Y over
time. Thus, I am interested in the relationship between the random effects
for the intercept and the slope, and I