Displaying 20 results from an estimated 9000 matches similar to: "R-help Digest, Vol 110, Issue 23"
2012 Apr 20
0
Survival, should I use (start,stop) and how?
Dear R users,
I fear this is terribly trivial but I'm struggling to get my head around it.
First of all, I'm using the "survival" package in R 2.12.2 on Windows Vista with the RExcel plugin. You probably only need to know that I'm using "survival" for this.
I have data collected from 180 or so individuals that were checked 7 times throughout a trial with set
2011 Sep 26
3
survival analysis: interval censored data
hello:
my data looks like:
time1 time2 event catagoria
2004 2006 1 C
2004 2005 0 C
2005 2010 1 E
2007 2009 1 C
2006 2007 0 E
2008 2010 0 C
2008 2010 1 E
...
and the census interval is 1 year
I have tried this
2007 May 02
3
the Surv function
Hi,
I'm trying to do a simple survival analysis on some data, and I'm having the
following problem (here's my code and the error message):
out <- Surv(fup,event=status)
Error in Surv(fup, event = status) : argument "time2" is missing, with no
default
>From reading the documentation, it seems that I should be able to simply
write: Surv(time1, event) if my data is
2010 Jan 12
0
Wishlist: Function 'difftime' to honor 'tzone' attribute (PR#14182)
Full_Name: Suharto Anggono
Version: 2.8.1
OS: Windows
Submission from: (NULL) (125.165.84.118)
PR#14076 inspired me to write this.
> t1 <- as.POSIXct("1970-01-01 00:00:00", tz="GMT")
> t2 <- as.POSIXlt("1970-01-01 00:00:00", tz="GMT")
> t1 - t2
Time difference of 7 hours
Above, t1 and t2 represent the same time in the same specified
2004 Apr 21
1
difference between coxph and cph
Hi. I am using Windows version of R 1.8.1. Being somewhat new to survival
analysis, I am trying to compare cph (Design) with coxph (survival) for use
with a survival data set.
I was wondering why cph and coxph provide me with different confidence
intervals
for the hazard ratios for one of the variables. I was wondering if I am
doing something wrong? Or if the two functions are calculating hazard
2012 Oct 18
1
Kaplan-Meier plotting quirks
Better would be to use interval censored data. Create your data set so that you have
(time1, time2) pairs, each of which describes the interval of time over which the tag was
lost. So an animal first captured at time 10 sans tag would be (0,10); with tag at 5 and
without at 20 would be (5,20), and last seen with tag at 30 would be (30, NA).
Then survit(Surv(time1, time2,
2008 Apr 09
2
fuzzy merge
Hi,
I would like to merge two data frames. It is just that I want the merging to be done with some kind of a fuzzy criterion. Let me explain.
My first data frame looks like this :
ID1 time1 dt
1 2008-01-02 13:11 10
2 2008-01-02 14:20 20
3
2010 Nov 15
3
merge two dataset and replace missing by 0
Hi r users,
I have two data sets (X1, X2). For example,
time1<-c( 0, 8, 15, 22, 43, 64, 85, 106, 127, 148, 169, 190 ,211 )
outpue1<-c(171 ,164 ,150 ,141 ,109 , 73 , 47 ,26 ,15 ,12 ,6 ,2 ,1 )
X1<-cbind(time1,outpue1)
time2<-c( 0 ,8 ,15 , 22 ,43 , 64 ,85 ,106 ,148)
output2<-c( 5 ,5 ,4 ,5 ,5 ,4 ,1 ,2 , 1 )
X2<-cbind(time2,output2)
I want to
2007 Jan 19
4
Newbie question: Statistical functions (e.g., mean, sd) in a "transform" statement?
Greetings listeRs -
Given a data frame such as
times
time1 time2 time3 time4
1 70.408543 48.92378 7.399605 95.93050
2 17.231940 27.48530 82.962916 10.20619
3 20.279220 10.33575 66.209290 30.71846
4 NA 53.31993 12.398237 35.65782
5 9.295965 NA 48.929201 NA
6 63.966518 42.16304 1.777342 NA
one can use "transform" to
2011 Jul 19
1
Measuring and comparing .C and .Call overhead
Further pursuing my curiosity to measure the efficiency of R/C++ interface, I
conducted a simple matrix-vector multiplication test using .C and .Call
functions in R. In each case, I measured the execution time in R, as well as
inside the C++ function. Subtracting the two, I came up with a measure of
overhead associated with each call. I assume that this overhead would be
non-existent of the entire
2008 May 09
1
predicting from coxph with pspline
Hello.
I get a bit confused by the output from the predict function when used
on an object from coxph in combination with p-spline, e.g.
fit <- coxph(Surv(time1, time2, status)~pspline(x), Data)
predict(fit, newdata=data.frame(x=1:2))
It seems like the output is somewhat independent of the x-values to
predict at. For example x=1:2 gives the same result as x=21:22. Does the
result span the
2009 May 15
1
Function Surv and interpretation
Dear everyone,
My question involves the use of the survival object.
We can have
Surv(time,time2,event, type=, origin = 0) (1)
As detailed on p.65 of:
http://cran.r-project.org/web/packages/survival/survival.pdf
My data (used in my study) is 'right censored' i.e. my variable corresponding to 'event' indicates whether a person is alive (0) or dead (1) at date last seen
2012 Nov 30
1
help on "stacking" matrices up
Dear All,
#I have the following code
Dose<-1000
Tinf <-0.5
INTERVAL <-8
TIME8 <-matrix(c((0*INTERVAL):(1*INTERVAL)))
TIME7 <-matrix(c((0*INTERVAL):(2*INTERVAL)))
TIME6 <-matrix(c((0*INTERVAL):(3*INTERVAL)))
TIME5 <-matrix(c((0*INTERVAL):(4*INTERVAL)))
TIME4 <-matrix(c((0*INTERVAL):(5*INTERVAL)))
TIME3 <-matrix(c((0*INTERVAL):(6*INTERVAL)))
TIME2
2010 Jan 16
2
Extracing only Unique Rows based on only 1 Column
To Whomever is Interested,
I have spent several days searching the web, help files, the R wiki
and the archives of this mailing list for a solution to this problem,
but nonetheless I apologize in advance if I have missed something
obvious.
The problem is this; I have a 5-column data frame with about 4.2
million rows, and want to create a new (and hopefully much smaller)
data frame that
2010 Sep 02
2
date
Hello all,
I've 2 strings that representing the start and end values of a date and
time.
For example,
time1 <- c("21/04/2005","23/05/2005","11/04/2005")
time2 <- c("15/07/2009", "03/06/2008", "15/10/2005")
as.difftime(time1,time2)
Time differences in secs
[1] NA NA NA
attr(,"tzone")
[1] ""
How can i
2011 Mar 10
2
Not sure how to handle hazard in my survival model
Hi R experts :)
I'm trying to carry out a survival model on my data, but I am unsure of
whether it's appropriate or if I should do something specific in regards to
hazard.
My data is time to death by predator where I have 8 prey and one predator in
the setting. This means that two prey can't possibly die at the same time
and I can't quite get my head around how to include this in
2013 Mar 21
1
All unique combinations
Dear all,
I would like to have all unique combinations in the following matrix
TimeIndex<- rbind (c(1,"Week_of_21_07-29_03"),
c(2,"Thursday_21_03"),
c(3,"Friday_22_03"),
c(4,"Saturday_23_03"),
c(5,"Sunday_24_03"),
c(6,"Monday_25_03"),
c(7,"Tuesday_26_03"),
2011 Nov 11
1
How to compute time interval?
time1 = 2008-03-09
time2 = 2010-9-10
How to compute how many years between time1 and time2?
Thanks!
best
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2009 Jan 27
2
Can I create a timeDate object using only year and week of the year values?
For a model I am working on, I have samples organized by year and week of
the year. For this model, the data (year and week) comes from the basic
sample data, but I require a value representing the amount of time since the
sample was taken (actually, for the purpose of the model, it is sufficient
to use the number of weeks from the middle of the sample week to the
present).
What I have found so
2007 Dec 16
4
improving a bar graph
Hello,
Below is the code for a basic bar graph. I was seeking advice
regarding the following:
(a) For each time period there are values from 16 people. How I can
change the colour value so that each person has a different colour,
which recurs across each of the three graphs/tie epriods?
(b) I have seen much more sophisticated examples using lattice (e.g
each person has a separate