Displaying 20 results from an estimated 2000 matches similar to: "survdiff for left-truncated data?"
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
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
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 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
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
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
2004 Aug 05
1
Post-hoc t-tests in 2-way repeated measure ANOVA
Hi all
I am running a 2-way repeated measure anova with 1 between-subjects
factor (Group=treatment, control), and 1 within-subject factor (Time of
measurement: time1, time2). I extract the results of the anova with:
summary(aov(effect ~ Group*Time + Error=Subj/Time, data=mydata))
Now, this must be clearly a dumb question, but how can I quickly extract
in R all the post-hoc t-tests for the
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
2012 Jan 26
1
3-parametric Weibull regression
Hello,
I'm quite new to R and want to make a Weibull-regression with the survival package. I know how to build my "Surv"-object and how to make a standard-weibull regression with "survreg".
However, I want to fit a translated or 3-parametric weibull dist to account for a failure-free time.
I think I would need a new object in survreg.distributions, but I don't know how
2009 Sep 11
1
What determines the unit of POSIXct differences?
Dear All,
what determines if a difference between POSIXct objects gets
expressed in days or seconds?
In the following example, it's sometimes seconds, sometimes days.
as.POSIXct('2009-09-01') - as.POSIXct(NA)
Time difference of NA secs
c(as.POSIXct('2009-09-01'), as.POSIXct(NA)) -
c(as.POSIXct('2009-09-01'), as.POSIXct('2009-08-31'))
Time differences in
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
2004 Jul 04
2
Random intercept model with time-dependent covariates, results different from SAS
Dear list-members
I am new to R and a statistics beginner. I really like the ease with which I can
extract and manipulate data in R, and would like to use it primarily. I've
been learning by checking analyses that have already been run in SAS.
In an experiment with Y being a response variable, and group a 2-level
between-subject factor, and time a 5-level within-subject factor. 2
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
2007 Dec 31
3
Survival analysis with no events in one treatment group
I'm trying to fit a Cox proportional hazards model to some hospital
admission data. About 25% of the patients have had at least one
admission, and of these, 40% have had two admissions within the 12
month period of the study. Each patients has had one of 4
treatments, and one of the treatment groups has had no admissions for
the period. I used:
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"),
2008 Oct 28
3
Dose Profile
Hi Everyone,
I have data in a long format e.g. there is one row per patient but each
follow-up appointment is included in the row. So, a snippet of the data
looks like this:
TrialNo Drug Sex Rand Adate1 Date1 Dose1 Time1 Adate2 Date2 Dose2
Time2 B1001029 LTG M 15719 30/04/2003 15825 150 106 29/08/2003 15946 200
227 B1117003 LTG M 15734 30/04/2003 15825 200 91 03/09/2003 15951 250 217
2005 Nov 23
1
survdiff for Left-truncated and right-censored data
dear all,
I would like to know whether survdiff and survReg function in the
survival package work for left-truncated and right-censored data.
If not, what other functions can i use to make comparison between two
survival curves with LTRC data.
thanks for any help given
sing yee
2011 Oct 06
3
Wide to long form conversion
I have some data 'myData' in wide form (attached at the end), and
would like to convert it to long form. I wish to have five variables
in the result:
1) Subj: factor
2) Group: between-subjects factor (2 levels: s / w)
3) Reference: within-subject factor (2 levels: Me / She)
4) F: within-subject factor (2 levels: F1 / F2)
5) J: within-subject factor (2 levels: J1 / J2)
As this is the
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