Displaying 20 results from an estimated 3000 matches similar to: "Missing data analysis in R"
2008 Feb 01
3
Converting a character string into an object variable
R-helpers:
Assume that I want to create a series of sequentially named R objects. For
example, I might want to call these objects V1, V2, V3 ... V50. To do this,
I thought of some sort of looping function like:
input.value <- seq(1:50) * 3
for(i in 1:50){
paste("V", i, sep="") <- input.value[i]
}
Of course this loop will not work since the paste function
2007 May 17
1
MICE for Cox model
R-helpers:
I have a dataset that has 168 subjects and 12 variables. Some of the
variables have missing data and I want to use the multiple imputation
capabilities of the "mice" package to address the missing data. Given
that mice only supports linear models and generalized linear models (via
the lm.mids and glm.mids functions) and that I need to fit Cox models, I
followed the previous
2007 Jan 12
7
Making TIFF images with rtiff
Many medical journals and publishers require that images, whether
photographs or line art, be submitted as high resolution .TIFF images.
One option for R users is to produce an image in one format and to
convert it to a .TIFF file using a second software program. My
experience has been that this option often results in images of poorer
quality, often with blurry contours, and a loss of
2008 Jan 21
3
'matrix' returns integer instead of decimal
R-helpers:
I am experiencing some odd behavior with the 'matrix' function that I have
not experienced before and was wondering if there is something that I was
missing in my code.
---------------------------------
> sessionInfo()
R version 2.6.1 (2007-11-26)
i386-pc-mingw32
locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
2007 Mar 13
1
Freeman-Tukey arcsine transformation
R-Experts:
Does anyone know if there are R functions to perform the Freeman-Tukey
double arcsine transformation and then backtransform it?
Thanks,
Brant Inman
Mayo Clinic
2007 Apr 25
1
prelim.norm() function not working
R-experts:
I am trying to reproduce some of Paul Allison's results in his little
green book on missing data (Sage 2002). The dataset for which I am
having problems, "usnews", can be found at:
http://www.ats.ucla.edu/stat/books/md/default.htm. I am working on a
Windows machine with R 2.5 installed, all packages up-to-date.
The problem has to do with the prelim.norm() function of the
2007 Apr 20
3
Opinion on R plots: connecting X and Y
Attention R users, especially those that are experienced enough to be
opinionated, I need your input.
Consider the following simple plot:
x <- rnorm(100)
y <- rnorm(100)
plot(x, y, bty='n')
A colleague (and dreaded SAS user) commented that she thought that my
plots could be "cleaned up" by connecting the X and Y axes. I know that
I can do that with bty='l' but I
2011 Feb 28
3
Measuring correlations in repeated measures data
R-helpers:
I would like to measure the correlation coefficient between the repeated measures of a single variable that is measured over time and is unbalanced. As an example, consider the Orthodont dataset from package nlme, where the model is:
fit <- lmer(distance ~ age + (1 | Subject), data=Orthodont)
I would like to measure the correlation b/t the variable "distance" at
2007 Jun 07
1
MITOOLS: Error in eval(expr, envir, enclos) : invalid 'envir' argument
R-users & helpers:
I am using Amelia, mitools and cmprsk to fit cumulative incidence curves
to multiply imputed datasets. The error message that I get
"Error in eval(expr, envir, enclos) : invalid 'envir' argument"
occurs when I try to fit models to the 50 imputed datasets using the
"with.imputationList" function of mitools. The problem seems to occur
2006 Oct 27
1
Censored Brier Score and Royston/Sauerbrei's D
System: R 2.3.1 on a Windows XP computer.
I am validating several cancer prognostic models that have been
published with a large independent dataset. Some of the models report a
probability of survival at a specified timepoint, usually at 5 and 10
years. Others report only the linear predictor of the Cox model.
I have used Harrell's c index for censored data (rcorr.cens) as a
measure of
2007 Mar 05
3
Mixed effects multinomial regression and meta-analysis
R Experts:
I am conducting a meta-analysis where the effect measures to be pooled
are simple proportions. For example, consider this data from
Fleiss/Levin/Paik's Statistical methods for rates and proportions (2003,
p189) on smokers:
Study N Event P(Event)
1 86 83 0.965
2 93 90 0.968
3 136 129 0.949
4 82 70 0.854
Total
2006 Nov 03
6
Import problem with S-Plus 7.0 dataset
I am running R 2.3.1 on a Windows XP machine. I am trying to import
some data into R that is stored as an S-Plus 7.0 .sdd file.
When I run the following command, I get this error:
> library(foreign)
> d <- read.S(file='H:\\Research\\data.sdd')
Error in read.S(file = "H:\\Research\\data.sdd") :
not an S object
The dataset is fairly large, roughly 13000 rows
2006 Nov 03
6
Import problem with S-Plus 7.0 dataset
I am running R 2.3.1 on a Windows XP machine. I am trying to import
some data into R that is stored as an S-Plus 7.0 .sdd file.
When I run the following command, I get this error:
> library(foreign)
> d <- read.S(file='H:\\Research\\data.sdd')
Error in read.S(file = "H:\\Research\\data.sdd") :
not an S object
The dataset is fairly large, roughly 13000 rows
2007 Apr 12
3
Putting 2 breaks on Y axis
R plotting experts:
I have a bivariate dataset composed of 300 (x,y) continuous datapoints.
297 of these points are located within the y range of [0,10], while 2
are located at 20 and one at 55. No coding errors, real outliers.
When plotting these data with a scatterplot, I obviously have a problem.
If I plot the full dataset with ylim = c(0,55), then I cannot see the
structure in the data in
2003 Jun 12
3
Multiple imputation
Hi all,
I'm currently working with a dataset that has quite a few missing
values and after some investigation I figured that multiple imputation
is probably the best solution to handle the missing data in my case. I
found several references to functions in S-Plus that perform multiple
imputation (NORM, CAT, MIX, PAN). Does R have corresponding functions?
I searched the archives but was not
2005 May 04
3
Imputation
I have timeseries data for some factors, and some missing values are there in those factors, I want impute those missing values without disturbing the distribution of that factor, and maintaining the correlation with other factors. Pl. suggest me some imputation methods.
I tried some functions in R like aregImpute, transcan. After the imputation I am unable to retrive the data with imputed
2007 Jan 06
2
Using VGAM's vglm function for ordinal logistic regression
R-Experts:
I am using the vglm function of the VGAM library to perform proportional
odds ordinal logistic regression. The issue that I would like help with
concerns the format in which the response variable must be provided for
this function to work correctly. Consider the following example:
------
library(VGAM)
library(MASS)
attach(pneumo)
pneumo # Inspect the format of the original dataset
2005 Jan 19
1
Imputation missing observations
>From Internet I downloaded the file Hmisc.zip and used it for R package updation. and R gave the message 'Hmisc' successfull unpacked.
But when I use the functions like aregImpute the package is displaying coundn't find the function
Where as in help.search it is giving that use of the function
>
2003 Dec 08
1
Design functions after Multiple Imputation
I am a new user of R for Windows, enthusiast about the many functions
of the Design and Hmisc libraries.
I combined the results of a Cox regression model after multiple imputation
(of missing values in some covariates).
Now I got my vector of coefficients (and of standard errors).
My question is: How could I use directly that vector to run programs such
as 'nomogram', 'calibrate',
2003 Jul 28
2
aregImpute: warning message re: acepack and mace
hi,
i'm trying to learn how to use aregImpute by doing the examples provided with
the package, and after installing Hmisc.1.6-1.zip (for Windows),
and running the very first example on R 1.7.1, i get an error message warning
me about "mace" (see below) and acepack.
i found the acepack package, but its filename ends in tar.gz
and i'm finding it difficult to open (because its