[R] quantile regression - estimation of CAViaR

2006-11-27 Thread jacinthe
How is it possible to estimate the conditional autoregressive Value-at-Risk model qantile_t(tau)=a0+a1*qantile_(t-1)(tau)+a2*abs(r_(t-1)) see http://www.faculty.ucr.edu/~taelee/paper/BLSpaper1.pdf (page 10)) of Engle & Manganelli in R? The qantile_(t-1)(tau)-term causes headache. Kind regard

[R] quantile regression and moments

2006-11-17 Thread jacinthe
Hi, how to derive an estimate of skewness and kurtosis out of a predicted distribution by quantile regression? Example: library(quantreg) data(airquality) airq <- airquality[143,] f <- rq(Ozone ~ ., data=airquality,tau=seq(0.01,0.99,0.01)) predict(f,newdata=airq) Any suggestions? Kind regards,

Re: [R] Quantile Regression: Measuring Goodness of Fit

2006-10-29 Thread Anupam Tyagi
Hi Martin, Efferz, Martin finance.uni-mainz.de> writes: > > Hi, > > how to measure the goodness of fit, when using the rq() function of quantreg? I need something like an R^2 for > quantile regression, a single number which tells me if the fit of the whole quantile process (not only for a > si

[R] Quantile Regression: Measuring Goodness of Fit

2006-10-27 Thread Efferz, Martin
Hi, how to measure the goodness of fit, when using the rq() function of quantreg? I need something like an R^2 for quantile regression, a single number which tells me if the fit of the whole quantile process (not only for a single quantile) is o.k. or not. Is it possible to compare the (condi

Re: [R] Quantile regression questions

2006-10-26 Thread roger koenker
Brian, It is hard to say at this level of resolution of the question, but it would seem that you might be able to start by considering each sample vector as as repeated measurement of the fiber length -- so 12 obs in the first 1/16th bin, 235 in the next and so forth, all associated with som

[R] Quantile regression questions

2006-10-26 Thread Brian Gardunia
I am relatively new to R, but am intrigued by its flexibility. I am interested in quantile regression and quantile estimation as regards to cotton fiber length distributions. The length distribution affects spinning and weaving properties, so it is desirable to select for certain distribution

Re: [R] Quantile Regression

2006-10-25 Thread roger koenker
> data(engel) > attach(engel) > rq(y~x) Call: rq(formula = y ~ x) Coefficients: (Intercept) x 81.4822474 0.5601806 Degrees of freedom: 235 total; 233 residual > rq(y~x)->f > f$tau [1] 0.5 url:www.econ.uiuc.edu/~rogerRoger Koenker email[EMAIL PROTECTED]

[R] Quantile Regression

2006-10-25 Thread jacinthe
Hi, how is it possible to retrieve the corresponding tau value for each observed data pair (x(t) y(t), t=1,...,n) when doing a quantile regression like rq.fit <- rq(y~x,tau=-1). Thank you for your help. Jaci -- __ R-help@stat.math.ethz.ch mailing li

[R] Quantile Regression Object

2006-07-14 Thread ricardosilva
Hi, I load my data set and separate it as folowing: presu <- read.table("C:/_Ricardo/Paty/qtdata_f.txt", header=TRUE, sep="\t", na.strings="NA", dec=".", strip.white=TRUE) dep<-presu[,3]; exo<-presu[,4:92]; Now, I want to use it using the wls and quantreg packages. How I change the data classes

Re: [R] quantile regression problem

2005-12-10 Thread Ted Harding
On 10-Dec-05 [EMAIL PROTECTED] wrote: > Dear List members, > > I would like to ask for advise on quantile regression in R. > > I am trying to perform an analysis of a relationship between > species abundance and its habitat requirements - > the habitat requirements are, however, codes - 0,1,2,3..

Re: [R] quantile regression problem

2005-12-10 Thread roger koenker
Since almost all (95%) of the observations are concentrated at x=0 and x=1, any fitting you do is strongly influenced by what would be obtained by simply fitting quantiles at these two points and interpolating, and extrapolating according to your favored model. I did the following: require(quan

[R] quantile regression problem

2005-12-10 Thread zuzmun
Dear List members, I would like to ask for advise on quantile regression in R. I am trying to perform an analysis of a relationship between species abundance and its habitat requirements - the habitat requirements are, however, codes - 0,1,2,3... where 0<1<2<3 and the scale is linear - so I wo

Re: [R] Quantile Regression, S-Function "Rreg"

2005-07-18 Thread Stefan Hoderlein
Dear Brian, thanks for your mail. For other reasons I need a local polynomial. The nonparametric regression code is very scetchy, but I have used it as base anyway. Best Stefan __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/list

[R] Quantile Regression, S-Function "Rreg"

2005-07-18 Thread Stefan Hoderlein
I have the following problem: I would like to do a nonparametric quatile regression. Thus far I have used the quantreg package and done a local quadratic, but it does not seem to work well. Alternatively, I have tried with an older S version I have the function rreg, and used rreg(datax,datay,me

Re: [R] Quantile Regression in R

2004-06-29 Thread roger koenker
The short answer to your question is that quantile regression estimates are estimating linear conditional quantile functions, just like lm() is used to estimate conditional mean functions. A longer answer would inevitably involve unpleasant suggestions that you should follow the posting guide: a.

[R] Quantile Regression in R

2004-06-29 Thread Ali Hirsa
I recently learn about Quantile Regression in R. I am trying to study two time series (attached) by Quantile Regression in R. I wrote the following code and do not know how to interpret the lines. What kind of information can I get from them? Correlation for quantiles, conditional probabilties

Re: [R] quantile regression

2004-03-12 Thread Christoph Scherber
OK, Thank you all very much for the help! Best regards Chris. Christoph Scherber wrote: Dear colleagues, How can I do quantile regression with R? Best regards Chris. __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-

Re: [R] quantile regression

2004-03-12 Thread Peter Dalgaard
Christoph Scherber <[EMAIL PROTECTED]> writes: > Dear colleagues, > > How can I do quantile regression with R? Package quantreg springs to mind... -- O__ Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenh

RE: [R] quantile regression

2004-03-12 Thread Liaw, Andy
Please read the footer of the message, and follow the link. Besides, you don't need people googling for you, do you? Andy > From: Christoph Scherber > > Dear colleagues, > > How can I do quantile regression with R? > > Best regards > Chris. > > __

[R] quantile regression

2004-03-12 Thread Christoph Scherber
Dear colleagues, How can I do quantile regression with R? Best regards Chris. __ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

[R] Quantile Regression Packages

2003-09-01 Thread Roger Koenker
I'd like to mention that there is a new quantile regression package "nprq" on CRAN for additive nonparametric quantile regression estimation. Models are structured similarly to the gss package of Gu and the mgcv package of Wood. Formulae like y ~ qss(z1) + qss(z2) + X are interpreted a