Displaying 20 results from an estimated 9000 matches similar to: "confidence interval in local polynomial regression"
2012 Jan 09
2
Joint confidence interval for fractional polynomial terms
Dear R users,
The package 'mfp' that fits fractional polynomial terms to predictors.
Example:
data(GBSG)
f <- mfp(Surv(rfst, cens) ~ fp(age, df = 4, select = 0.05)
+ fp(prm, df = 4, select = 0.05), family = cox, data = GBSG)
print(f)
To describe the association between the original predictor, eg. age and
risk for different values of age I can plot it the polynomials
2009 Dec 08
1
coefficients of each local polynomial from locfit
Hi list,
This was asked a couple of years ago but I can't find a resolution. Is
there any way to get the coefficients from one of the local polynomial fits
in locfit. I realize that locfit only constructs polynomials at a handful
of intelligently selected points and uses interpolation to predict any other
points. I would like to know the terms of the polynomials at these points.
It seems
2006 Mar 29
2
bivariate case in Local Polynomials regression
Hi:
I am using the package "KernSmooth" to do the local polynomial regression. However, it seems the function "locpoly" can only deal with univariate covaraite. I wonder is there any kernel smoothing package in R can deal with bivariate covariates? I also checked the package "lcofit" in which function "lcofit" can indeed deal with bivariate case. The
2012 Dec 06
1
bootstrap based confidence band
I'm trying to find a bootstrap based confidence band for a linear model.
I have created a data set with X and Y
X=runif(n,-1.25,1.25)
e=rnorm(n,0,1)
Y=exp(3*X)+5*sin((30*X)/(2*pi))+2*e
fit=lm(Y~X)
summary(fit)
I define a bootstrap function named PairedBootstrap which is not listed here. Than I try many ways to find the confidence band. One way is to predict Y using the model I get above for
2007 Jun 08
1
pointwise confidence bands or interval values for a non parametric sm.regression
Dear all,
Is there a way to plot / calculate pointwise confidence bands or
interval values for a non parametric regression like sm.regression?
Thank you in advance.
Regards,
Martin
2005 Apr 14
1
LOCFIT: What's it doing?
Dear R-users,
One of the main reasons I moved from GAUSS to R (as an econometrician) was because of the existence of the library LOCFIT for local polynomial regression. While doing some checking between my former `GAUSS code' and my new `R code', I came to realize LOCFIT is not quite doing what I want. I wrote the following example script:
2004 Sep 30
1
Vectorising and loop (was Re: optim "a log-likelihood function")
>From: Sundar Dorai-Raj <sundar.dorai-raj at PDF.COM>
>Reply-To: sundar.dorai-raj at PDF.COM
>To: Zhen Pang <nusbj at hotmail.com>
>CC: r-help at stat.math.ethz.ch
>Subject: Vectorising and loop (was Re: [R] optim "a log-likelihood
>function")
>Date: Wed, 29 Sep 2004 18:21:17 -0700
>
>
>
>Zhen Pang wrote:
>
>>
>>I also use
2005 Dec 29
1
use of predict() with confidence/prediction bands
To my understanding, a confidence interval typically covers a single
valued parameter. In contrast, a confidence band covers an entire line
with a band. In regression, it is quite common to construct confidence
and prediction bands. I have found that many people are connecting
individual confidence/prediction interval values produced with
predict(object,sd.fit=T,type="conf/pred") and
2008 Jun 18
1
Pointwise Confidence Bounds on Logistic Regression
Hi all. I hope I have my terminology right here...
For a simple lm, one can add ?pointwise confidence bounds? to a fitted line
using something like
>predict(results.lm, newdata = something, interval = "confidence")
(I'm following DAAG page 154-155 for this)
I would like to do the same thing for a glm of the logistic regression type,
for instance, the example in MASS pg
2008 Sep 23
1
bandwidth selection for locpoly
Hello All,
Is there a local bandwidth selection routine for local polynomial
regression (locpoly) ?
Thanks
Chinthaka Kuruwita
2007 Jun 04
0
Local polynomial regression using locfit
I have a dataset of pregnancy values for multiple years (and ages, not
included) with missing years. I would like to use local polynomial
regression to smooth the values and estimate for the missing years. I
would also like to use GCV to justify the smoothing parameter selection.
When using locfit() with lp() I found that the gcvplot function does not
work as it is looking for an alpha value to
2003 Oct 21
5
run R under linux
Dear all,
Our department uses the linux system and we are not allowed to submit job
directly. We must make a batch to submit through "qmon".
so, I make a foo.sh file, which only contains one line: nohup R --vanilla <
foo.txt > foo.results
foo is all my codes. It is a simulation of 200 times. I set the seed at the
beginning. It is to estimate the success probability, which is
2010 Mar 27
0
data fitting and confidence band
Hello,
I am fitting data using different methods e.g. Local Polynomial and Smoothing splines. The data is generated out of a true function model with added normally distributed noise.
I would like to know "how often the confidence band for all points simultaneously contain all true values". I can answer the question for one point in the following way:
e.g.
#
2003 Nov 03
1
svm in e1071 package: polynomial vs linear kernel
I am trying to understand what is the difference between linear and
polynomial kernel:
linear: u'*v
polynomial: (gamma*u'*v + coef0)^degree
It would seem that polynomial kernel with gamma = 1; coef0 = 0 and degree
= 1
should be identical to linear kernel, however it gives me significantly
different results for very simple
data set, with linear kernel
2007 Aug 15
1
Polynomial fitting
Hi everybody!
I'm looking some way to do in R a polynomial fit, say like polyfit
function of Octave/MATLAB.
For who don't know, c = polyfit(x,y,m) finds the coefficients of a
polynomial p(x) of degree m that fits the data, p(x[i]) to y[i], in a
least squares sense. The result c is a vector of length m+1 containing
the polynomial coefficients in descending powers:
p(x) = c[1]*x^n +
2004 Dec 03
3
Computing the minimal polynomial or, at least, its degree
Hi,
I would like to know whether there exist algorithms to compute the
coefficients or, at least, the degree of the minimal polynomial of a square
matrix A (over the field of complex numbers)? I don't know whether this
would require symbolic computation. If not, has any of the algorithms been
implemented in R?
Thanks very much,
Ravi.
P.S. Just for the sake of completeness, a
2001 Jun 13
2
multivariate local regression with locfit
I've been trying to run locfit on data with 6 inputs and 1 output in R.
Whenever I make a prediction for the same exact data that the model was
built on though, I get significant discrepancies between the fitted outputs
of the prediction and the actual data. I have scaled the inputs, tweaked
the alpha parameter, and played around with a lot of the other variables as
well. Is their some kind
2004 Oct 16
7
sapply and loop
Dear all,
I am doing 200 times simulation. For each time, I generate a matrix and
define some function on this matrix to get a 6 dimension vector as my
results.
As the loop should be slow, I generate 200 matrice first, and save them into
a list named ma,
then I define zz<-sapply(ma, myfunction)
To my surprise, It almost costs me the same time to get my results if I
directly use a loop
2004 Oct 16
7
sapply and loop
Dear all,
I am doing 200 times simulation. For each time, I generate a matrix and
define some function on this matrix to get a 6 dimension vector as my
results.
As the loop should be slow, I generate 200 matrice first, and save them into
a list named ma,
then I define zz<-sapply(ma, myfunction)
To my surprise, It almost costs me the same time to get my results if I
directly use a loop
2010 Oct 05
2
Using as.polynomial() over a matrix
Hello All
First - a warning. I'm not very R or programming savvy.
I am trying to do something without much luck, and have scoured help-pages, but nothing has come up. Here it is:
I have a matrix (m) of approx 40,000 rows and 3 columns, filled with numbers.
I would like to convert the contents of this matrix into another matrix (m_p), where the numbers of (m) have been coerced into a