Displaying 12 results from an estimated 12 matches similar to: "Weibull survival modeling with covariate"
2005 Jun 23
1
Stop Warnings for Invalid Factor Level, NAs generated?
How can I stop the following warning from occuring?
invalid factor level, NAs generated in: "[<-.factor"(`*tmp*`, iseq, value =
structure(1, .Label = "12", class = "factor"))
The Label messages are for "5", "8", "12" and "46". I want the NAs to be
generated as needed.
Is this causing R to slow down by generating the warning
2011 Apr 27
3
MASS fitdistr with plyr or data.table?
I am trying to extract the shape and scale parameters of a wind speed
distribution for different sites. I can do this in a clunky way, but
I was hoping to find a way using data.table or plyr. However, when I
try I am met with the following:
set.seed(144)
weib.dist<-rweibull(10000,shape=3,scale=8)
weib.test<-data.table(cbind(1:10,weib.dist))
2009 Aug 25
3
Covariates in NLS (Multiple nonlinear regression)
Dear R-users,
I am trying to create a model using the NLS function, such that:
Y = f(X) + q + e
Where f is a nonlinear (Weibull: a*(1-exp(-b*X^c)) function of X and q is a covariate (continous variable) and e is an error term. I know that you can create multiple nonlinear regressions where x is polynomial for example, but is it possible to do this kind of thing when x is a function with unknown
2007 May 16
3
Filled step-function?
Hello,
I'd like to generate a filled step-function in R as you can see in the
attachement (image is generated by grapher, but I need a freely
available alternative). The problem is, that I don't know, how to fill
it up. My code right now looks like this:
pH <- c(0,6.1,6.1,6.3,6.6,7.3,0)
Tiefe <- c(0,0,10,40,80,120,10)
plot(pH,Tiefe,type="s",main="Tiefenfunktion
2006 Jun 24
2
smoothing splines and degrees of freedom
Hi,
If I set df=2 in my smooth.spline function, is that equivalent to running
a linear regression through my data? It appears that df=# of data points
gives the interpolating spline and that df = 2 gives the linear
regression, but I just want to confirm this.
Thank you,
Steven
2006 Dec 28
0
RODBC not working when connecting to a Sybase database
What is this error message about and how do I troubleshoot it?
> sqlTables(channel)
Error in .Call("RODBCFetchRows", attr(channel, "handle_ptr"), max, buffsize, :
negative length vectors are not allowed
The channel was created as such
channel <- odbcConnect("Labdata")
I think this is telling me that my odbcConnect command worked
>
2005 Feb 24
2
survreg with gamma distribution: re-post
Dear r-help subscribers,
A couple of weeks ago I sent the following message to the r-help mail
list. It hasn't generated any response, and I could really use some help
on this. Anyone able to help?
Thanks again,
Roger Dungan
>>
I am working on some survival analysis of some interval censored failure
time data in R. I have done similar analysis before using PROC LIFEREG
in SAS. In
2009 Oct 21
3
Temperature Prediction Model
Greetings!
As part of my research project I am using R to study temperature data
collected by a network. Each node (observation point) records temperature of
its surroundings throughout the day and generates a dataset. Using the
recorded datasets for the past 7 days I need to build a prediction model for
each node that would enable it to check the observed data against the
predicted data. How can
2005 Dec 16
25
I Would Really Like to Try RoR but...
it''s been a nightmare trying to set it up. I keep getting a an
Application Error message when I try to navigate to a url which should
be taken care of by my newly created controllers. For instance, I
wanted to test RoR out so I created a MyTest controller which should
allow me to navigate something like:
http://localhost/rubytest/MyTest
but it does not. I have no problem getting
2010 Mar 23
0
Frozen hash problem
I''d like to delete some records before saving them. I ran this
experiment:
before_save :prune_lab_datas
def prune_lab_datas
lab_datas.each do |lab_data|
lab_data.destroy
end
raise lab_datas.to_yaml
end
But nothing seems to be deleted in the hash:
---
- &id001 !ruby/object:LabData
attributes:
created_at: 2010-03-21 22:16:06
unit_id: "3"
2002 Mar 12
1
RArcInfo Package, get.bnddata()
I am having trouble using get.bnddata() in the RArcInfo package. I
installed the version 0.2 binary of the package for Windows and am using R
1.4.1 on Windows NT 4.0. I have had no problems importing and plotting arc
data with get.arcdata() and plotarc(). plotpal() also works fine. I've
been able to use get.arcdata(), get.labdata(), get.paldata(),
get.tablenames(), get.tablefields(),
2005 Jan 27
0
Survreg with gamma distribution
Dear r-help subscribers,
I am working on some survival analysis of some interval censored failure
time data in R. I have done similar analysis before using PROC LIFEREG
in SAS. In that instance, a gamma survival function was the optimum
parametric model for describing the survival and hazard functions. I
would like to be able to use a gamma function in R, but apparently the
survival package does