Displaying 20 results from an estimated 1392 matches for "baseline".
2010 Sep 07
2
some questions about longitudinal study with baseline
...So would like to
resend the message, hope to get any fresh attention. Since this is not purely
lme technical question, so I also cc-ed R general mailing list, hope to get some
suggestions from there as well.
I asked some questions on how to analyze longitudinal study with only 2 time
points (baseline and a follow-up) previously. I appreciate many useful comments
from some members, especially Dennis Murphy and Marc Schwartz who refered the
following paper addressing specifically this type of study with only 2 time
points:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121605/
Basically, wit...
2010 Oct 05
3
SweaveInput + keep.source = TRUE trouble
...h keep.source = TRUE
Symptom:
SInput is taken from too far down the input file (the shift is the number of
lines of the included file). Is that known? Searching didn't turn up anything,
yet I think there are more people than just me using keep.source.
Example:
$ ~/tmp/R-beta/bin/R CMD Sweave baseline.Rnw &&
mv baseline.tex baseline.devel.tex &&
R CMD Sweave baseline.Rnw &&
mv baseline.tex baseline.2.11.tex &&
diff -u baseline.2.11.tex baseline.devel.tex
gives:
--- baseline.2.11.tex 2010-10-05 11:33:49.000000000 +0200
+++ baseline.devel.tex 2010-10-05 11:33:49.00...
2012 Apr 27
2
Deleting observations from baseline that don't appear in follow up
Hello all,
I'm almost embarrassed to post this , it seems so easy. Suppose I have a
baseline and follow up survey but some people are missing in the follow up:
> baseline<-data.frame(id=c(3,5,7,9,12), data= runif(5))
> follow.up<-data.frame(id=c(3,7,9,12), data= runif(4))
> baseline
id data
1 3 0.66771988
2 5 0.28794744
3 7 0.01892821
4 9 0.64863175
5 12 0.86485...
2006 Oct 22
1
Multilevel model ("lme") question
...s) model using the lme function
(package nlme) in R 2.4.0. As a mixed-effects newbie I'm neither sure about
the modeling nor the correct R syntax.
My data is structured as follows: For each subject, a quantity Y is measured
at a number (>= 2) of time points. Moreover, at time point 0 ("baseline"), a
quantity X is measured for each subject (I am interested to see whether X,
or log(X), is a predictor of Y). I saw in some examples that time-invariant
predictors should be repeated for all rows of a subject, which is why I
copied the baseline value of X also to time points > 0. The res...
2009 May 22
2
Error in FUN with tapply and by
A subset of my raw data looks like this:
--------------
"Grip" "Technique" "Baseline.integrated" "Task"
"Stroke..direction." "Engag" "Disen"
"PenDG" "PenUG" "PenDS"
"PenUS" "Duration"
-------------
"Tripod","Barrel&...
2012 Sep 01
5
R_closest date
...0 179 2
I need to find, the single observation, which has the closest date of 'OBS_DATE' to 'IDX_DT'.
For example, for 'PT_ID' of 4549, I need row 13, of which the OBS_DATE is just one day away from IDX_DT.
I was thinking about using abs(), and I got this:
baseline<- function(x){
+
+ #remove all uncessary variables
+ baseline<- x[,c("PT_ID","DAYS_DIFF")]
+
+ #get a list of every unique ID
+ uniqueID <- unique(baseline$PT_ID)
+
+ #make a vector that will contain the smallest DAYS_DIFF
+ first <- rep(-99,length(unique...
2005 Jun 10
1
Estimate of baseline hazard in survival
Dear All,
I'm having just a little terminology problem, relating the language used in
the Hosmer and Lemeshow text on Applied Survival Analysis to that of the
help that comes with the survival package.
I am trying to back out the values for the baseline hazard, h_o(t_i), for
each event time or observation time.
Now survfit(fit)$surv gives me the value of the survival function,
S(t_i|X_i,B), using mean values of the covariates and the coxph() object
provides me with the estimate of the linear predictors, exp(X'B).
If S(t_i|X_i,B)=S_o(t_i)^exp(...
2011 Jan 18
2
Baseline terms for lrm
Dear R-help and Prof. Harrell:
My question concerns the baseline state for continuous variable in lrm()
within the RMS package.
I have a model which can be reduced to:
lrm(FT ~ rcs(V1, c(0, 1,5))
The model makes perfect sense if the baseline state is where V1>=5 but
the model makes no sense if the baseline category is 0 (which I had
expected).
Can someo...
2008 Sep 16
2
creating baseline variable from a longitudinal sequence
...this problem:
I have a dataset that is in the format below,
ID time Y Age
1 0 195 23.1
1 2 204 23.3
1 4 202 23.5
2 0 170 22.0
2 3 234 22.2
3 0 208 24.4
3 2 194 24 .7
3 3 204 24.9
I wish to remove all the measurements at time point 0 and convert them to a baseline variable as follows;
ID time Y Age baseline
1 2 204 23.3 195
1 4 202 23.5 195
2 3 234 22.2 170
3 2 194 24 .7 208
3 3 204 24.9 208
Thanks.
regards
John
[[alternative HTML version deleted]]
2004 Sep 17
1
Confused about specifying plot colors as RGB values
...happen? I need to be able
to specify an array of rgb values for the 'col' parameter.
colnames.col <- c("black", "red", "blue", "green")
colnames.rgb <- apply(as.matrix(colnames.col), 1, col2rgb)
dimnames(colnames.rgb)[[2]] <- colnames.col
baseline <- 1:32
offset2 <- 2*baseline
offset3 <- 3*baseline
offset4 <- 4*baseline
offsets <- cbind(offset2, offset3, offset4)
# Produces expected result
X11()
matplot(baseline, col = colnames.col[1], type = "l")
matlines(offsets, col = colnames.col[-1])
# Displays a ??yellow?? li...
2009 Dec 16
1
Baseline survival estimate
Dear R-help,
I am trying to obtain the baseline survival estimate of a fitted Cox model
(S_0 (t)). I know that previous posts have said use 'basehaz' but this
gives the baseline hazard function and not the baseline survival estimate.
Is there a way to obtain the baseline survival estimate or do I have to use
the formula which does somet...
2001 Feb 22
3
[newbie] Cox Baseline Hazard
...catch up). I've discovered R
recently while trying to find a statistical program in order to avoid
rebooting my computer under windows when I need to do some statistical
work.
And here is my first question.
I'm actually trying to model a survival curve using a cox model.
But I need the baseline cumulative hazard. I've been looking around on
the web and the archives, and I found that it as to do with the
nelson-aalen estimation.
But I must not understand all the doc very well, because I can't get
the baseline hazard.
Could you help me, please.
Best regards.
PS : I hope you'...
2011 Jan 18
0
analysis strategy - baseline and repeated measure
Hi, assume that I have a repeated measure dataset with 3 time points: baseline,
day 5 and day 10. There are 4 treatment groups (vehicle, treatment 1, treatment
2 and treatment 3). 20 subjects per treatment group. A simple straight-forward
way to analyze the data is to use mixed model:
model 1:
obj <- lmer(y ~ treatment * time +(time|subject)) where time is numeric with...
2008 Jun 04
1
I am doing something wrong....
...odule/INFO/issue
./files/module/NIS
./files/module/NIS/nsswitch.conf
./fileserver.conf
./manifests
./manifests/nodes.pp
./manifests/site.pp
./manifests/templates.pp
./puppet.conf
./modules
./modules/ssh
./modules/ssh/manifests
./modules/ssh/manifests/ssh.pp
./modules/ssh/manifests/init.pp
./modules/baseline
./modules/baseline/plugins
./modules/baseline/plugins/puppet
./modules/baseline/plugins/puppet/type
./modules/baseline/plugins/puppet/type/lines.pp
./modules/baseline/manifests
./modules/baseline/manifests/baseline.pp
./modules/baseline/manifests/init.pp
./modules/openvz
./modules/openvz/manifests...
2010 Mar 23
2
Sample size for proportion, not binomial
Hello, I am looking for a sample size function for samples sizes, to test proportions that are not binomial proportions. The proportions represent a ratio of (final measure) / (baseline measure) on the same experimental unit. Searches using RSeek and such bring multiple hits for binomial proportions, but that doesn't seem to fit my situation. Perhaps there's some standard terminology from a different field that would provide better hits than deeming this a 'rate'...
2007 Feb 20
1
baseline fitters
I am pretty pleased with baselines I fit to chromatograms using the
runquantile() function in caTools(v1.6) when its probs parameter is
set to 0.2 and its k parameter to ~1/20th of n (e.g., k ~ 225 for n ~
4500, where n is time series length). This ignores occasional low-
side outliers, and, after baseline subtraction, I can re-...
2011 Oct 01
4
Is the output of survfit.coxph survival or baseline survival?
Dear all,
I am confused with the output of survfit.coxph.
Someone said that the survival given by summary(survfit.coxph) is the
baseline survival S_0, but some said that is the survival S=S_0^exp{beta*x}.
Which one is correct?
By the way, if I use "newdata=" in the survfit, does that mean the survival
is estimated by the value of covariates in the new data frame?
Thank you very much!
Koshihaku
--
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2008 Feb 05
1
Extracting level-1 variance from lmer()
...: subscript out of bounds
##########################################################
set.seed(500)
n.timepoints <- 4
n.subj.per.tx <- 20
sd.d <- 5;
sd.p <- 2;
sd.res <- 1.3
drug <- factor(rep(c("D", "P"), each = n.timepoints, times =
n.subj.per.tx))
drug.baseline <- rep( c(0,5), each=n.timepoints, times=n.subj.per.tx )
#Patient <- rep(1:(n.subj.per.tx*2), each = n.timepoints)
Patient.baseline <- rep( rnorm( n.subj.per.tx*2, sd=c(sd.d, sd.p) ),
each=n.timepoints )
time.baseline <- rep(1:n.timepoints,n.subj.per.tx*2)*as.numeric(drug=="D"...
2011 Jan 03
3
Inverse Gaussian Distribution
Dear,
I want to fit an inverse gaussion distribution to a data set.
The predictor variables are gender, area and agecategory.
For each of these variables I've defined a baseline
e.g.
#agecat: baseline is 3
data<-transform(data, agecat=C(factor(agecat,ordered=TRUE),
contr.treatment(n=6,base=3)))
The variable 'area' goes from A to F (6 areas: A,B,C,D,E,F)
How can i manipulate the data to set the baseline of area to C?
R is producing errors when I'm tryi...
2016 Jun 30
0
New Aggressive Dead Code Elimination (updated)
...ce frontier to
incrementally identify control dependence sources for live operations
to determine when branch operations are live. It adds a new fix-up
phase to correct update phi-nodeswhen control flow changes.
Below are compile time and performance impacts based on Facebook
internal code sets.
Baseline ADCE compared to new ADCE compile time, -O3 removing loops
Comparing compile times for ~400 source files from folly code base
"baseline" is total time in seconds for all files
"net_difference" is increase due to changes
"percent" is increase expressed aa persent of ba...