Displaying 20 results from an estimated 4000 matches similar to: "Product integral in R"
2007 Oct 23
2
2-D numerical integration over odd region
Hello all,
I'm hoping to find a way to evaluate the following sort of integral in R.
\int_a^b \int_{g(y)}^Inf f(x,y) dx dy.
The integral has no closed form and so must be evaluated numerically. The "adapt" package provides
for multidimensional integration but does not appear to allow the limits of integration to be a
function. I need to evaluate a number of integrals of this
2004 Oct 21
2
How to calculate a double integral ...?
Dear R-Friends,
How can I calculate a double integral like
\int_a^b \int_c^y g(x, y) dx dy
where a, b, c are constants, g(x, y), e.g.,
g(x, y) = tan(x + y).
I tried to nested integrate() and adapt(),
but none of them working, seemingly due to the
limits can not be specified constants.
Best regards,
C. Joseph Lu
Department of Statistics
National Cheng-Kung University
Voice:
2013 Feb 16
3
two dimensional integration
Dear R-users,
I'm wondering how to calculate this double integral in R:
int_a^b int_c^y g(x, y) dx dy
where g(x,y) = exp(- alpha (y - x)) * b
Thanks for answering!
Cheers,
Alui
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2011 Nov 06
1
Double integration using R
Hi,
I have a function that I need to do double integration:
\int^T_0 \int^t_0 N(\delta / \sigma \sqrt(u)) (1-N(\delta / \sigma
\sqrt(u))) du dt
where N(x) is a standard normal probability of x.
I start off by writing an inner integral into a function. Meaning
\int^t_0 N(\delta,\sigma \sqrt(u)) (1-N(\delta,\sigma \sqrt(u))) du.
Then calling integrate function on this function. This
2008 Feb 19
2
numerical integration of a ftn of 2 variables
Dear R gurus,
To start, let me confess to not being an experienced programmer, although I have used R fairly
extensively in my work as a
graduate student in statistics.
I wish to find the root of a function of two variables that is defined by an integral which must be
evaluated numerically.
So the problem I want to solve is of the form: Find k such that f(k)=0, where f(y) = int_a^b
g(x,y)
2008 Feb 14
4
Kaplan Meier function
Hi all,
I am trying to draw a Kaplan-Meier curve and I found online that Kaplan -
Meier estimates are computed with a function called km in the event package.
Is there an update for that because when I choose to download packages in
R,. there is no package called event, even though I have selected all the
repositories.
Thanks in advance,
Eleni
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2012 Jan 11
2
Finding percentile of a value from an empirical distribution
Hello,
I am not sure how to do this in R. Any suggestion would be
appreciated. I have a vector of values from where I build an empirical
CDF. For example:
> x <- seq(1,100)
> x <- sample(x,1000,replace=T)
> quantile(x,probs=seq(0,1,.05))
0% 5% 10% 15% 20% 25% 30% 35% 40% 45%
50% 55%
1.00 5.00 10.00 16.00 20.00 25.00 31.00 36.00 41.00
2013 Nov 20
4
How to stop Kaplan-Meier curve at a time point
Hello R users
I have a question with Kaplan-Meier Curve with respect to my research. We
have done a retrospective study on fillings in the tooth and their survival
in relation to the many influencing factors. We had a long follow-up time
(upto 8yrs for some variables). However, we decided to stop the analysis at
the 6year follow up time, so that we can have uniform follow-up time for
all the
2001 Mar 11
2
Kaplan-Meier for left-truncated, right-censored data
Is it possible to calculate Kaplan-Meier for left-truncated,
right-censored data using survival5?
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2004 Jan 07
2
Survival, Kaplan-Meier, left truncation
Dear all,
I have data from 1970 to 1990 for people above age 50.
Now I want to calculate survival curves by age starting at age 50 using the
Kaplan Meier Estimator.
The problem I have is that there are already people in 1970 who are older
than 50 years.
I guess this is called delayed entry or left truncation (?).
I thought the code would be:
roland <- survfit(Surv(time=age.enter,
2013 Apr 11
3
odfWeave: Some questions about potential formatting options
Hello All,
Learning to use the odfWeave package. I really like the package. It has good documentation, makes some very nice looking tables, and seems to have lots of options for customizing output.
There are a few things I'd like to do that don't seem to be covered in the documentation though. So I'm not sure if they're possible or not.
Here's a list of some things I'd
2010 Sep 10
2
survfit question
Hi,
I am attempting to graph a Kaplan Meier estimate for some claims using the survfit function. However, I was wondering if it is possible to plot a cdf of the kaplan meier rather than the survival function. Here is some of my code:
library(survival)
Surv(claimj,censorj==0)
survfit(Surv(claimj,censorj==0)~1)
surv.all<-survfit(Surv(claimj,censorj==0)~1)
summary(surv.all)
plot(surv.all)
2011 Jul 13
2
life table and Kaplan-Meier
Hello, I have a question about the function lifetab in package KMsurv.
The description of the output value surv says "the estimated survival
function at the start of the intervals".
Are these estimates the ones calculated via Kaplan-Meier probability of
survival ?
Thanks in advance!
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2010 Apr 19
2
Kaplan-Meier survfit problem
When I try to the code from library(survival) of library(ISwR),
the following code
survfit(Surv(days,status==1))
that could produce Kaplan-Meier estimates shows the following error
"Error in survfit(Surv(days, status == 1)) :
Survfit requires a formula or a coxph fit as the first argument"
How it can be done in R.2.10
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2005 Nov 22
3
Weibull and survival
Hi
I have been asked to provide Weibull parameters from a paper using
Kaplan Meir survival analysis.
This is something I am not familiar with.
The survival analysis in R works nicely and is the same as commercial
software (only the graphs are superior in R).
The Weibull does not and produces an error (see below).
Any ideas why this error should occur?
My approach may be spurious.
2010 Dec 10
2
survival package - calculating probability to survive a given time
Dear R users,
i try to calculate the probabilty to survive a given time by using the
estimated survival curve by kaplan meier.
What is the right way to do that? as far as is see i cannot use the
predict-methods from the survival package?
library(survival)
set.seed(1)
time <- cumsum(rexp(1000)/10)
status <- rbinom(1000, 1, 0.5)
## kaplan meier estimates
fit <- survfit(Surv(time,
2006 Oct 10
4
generate random numbers that sum up to 1
As I have previously asked, in response to a similar
question: Is this a homework problem?
cheers,
Rolf Turner
rolf at math.unb.ca
2005 Feb 04
5
How to access results of survival analysis
Hello,
it seems that the main results of survival analysis with package survival
are shown only as side effects of the print method.
If I compute e.g. a Kaplan-Meier estimate by
> km.survdur<-survfit(s.survdur)
then I can simply print the results by
> km.survdur
Call: survfit(formula = s.survdur)
n events median 0.95LCL 0.95UCL
100.0 58.0 46.8 41.0 79.3
Is
2011 Jun 27
7
cumulative incidence plot vs survival plot
Hi, I am wondering if anyone can explain to me if cumulative incidence (CI) is
just "1 minus kaplan-Meier survival"? Under what circumstance, you should use
cumulative incidence vs KM survival? If the relationship is just CI =
1-survival, then what difference it makes to use one vs. the other?
And in R how I can draw a cumulative incidence plot. I know I can make a
Kaplan-Meier
2012 Oct 16
2
R Kaplan-Meier plotting quirks?
Hello. I apologize in advance for the VERY lengthy e-mail. I endeavor to
include enough detail.
I have a question about survival curves I have been battling off and on for
a few months. No one local seems to be able to help, so I turn here. The
issue seems to either be how R calculates Kaplan-Meier Plots, or something
with the underlying statistic itself that I am misunderstanding. Basically,