search for: logisitc

I have uploaded a datafile that contains the following two variables: time (X value) and response (Y value). This is a fairly extensive file (with > 16000 entries). I have two questions: 1. I want to use the following equation to regress Y on X: Y-hat = min + (max-min)/(1 + (X/EC50)^Hillslope). Here is my R command: nlsout <- nls(Y ~ (0 - (100-0)/(1 + (X/EC50)^hill)), start=c(EC50=125,

...e of an event (factor) having more than 2 levels with several continuous predictors. The model being ordinal, I was waiting the glm function to return several intercepts, which is not the case when looking to my results (I only have one intercept). I finally managed to perform an ordinal polytomous logisitc regression with the polr function, which gives several intercepts. But does anyone know what was the model performed with glm and why only one intercept was given ? Thanks a lot for your help ! -- View this message in context: http://r.789695.n4.nabble.com/glm-prediction-of-a-factor-with-several-...

..., I found that using different contrasts (e.g. contr.helmert vs. contr.treatment) will generate different fitted probabilities from multinomial logistic regression using multinom(); while the fitted probabilities from binary logistic regression seem to be the same. Why is that? and for multinomial logisitc regression, what contrast should be used? I guess it's helmert? here is an example script: library(MASS) library(nnet) #### multinomial logistic options(contrasts=c('contr.treatment','contr.poly')) xx<-multinom(Type~Infl+Cont,data=housing[-c(1,10,11,22,25,30),]) yy&l...

Hi all, I am trying to make a script that prints all possible models from a model I've created using nls(). It is a logisitc model which in total includes 13 variables. So its >8000 models I need to create, which I don't want to do manually. I've tried modify scripts made for linear models with no results. I've tried these scripts on a two variable model (c,a1 and a2 is what I want to estimate here. Where...

...it in R (with the read.spss command) which conists of scale (continuous) variable "adiponectin" and the corresponding categorical value "death" (0=No, 1=Yes). In all there are 60 observations (among which there are 26 events). I am trying to do rcspline.plot (model="logisitc", nk=5, knots=NULL) however the error message that i get is "fewer than 6 non missing observations". I have repeated the process with a similar dataset of 300 observations (instead of 60) and I still get the same message. Can anybody suggest a hint ? Kind regards Georgi...

...e in a second posting that has a workable example. JN On 09/13/2011 06:00 AM, r-help-request at r-project.org wrote: > Message: 79 > Date: Mon, 12 Sep 2011 17:12:14 -0700 > From: sg <listerr01 at gmail.com> > To: r-help at r-project.org > Subject: [R] nls, the four parameter logisitc equation, and prediction > band > Message-ID: > <CAELtrnGUXprB3q0FPvMFamUjtkufnwaFju_BDunU-r-e2cKagg at mail.gmail.com> > Content-Type: text/plain > > I have uploaded a datafile that contains the following two variables: time > (X value) and response (Y value). This i...

Dear R helpers! Let me first wish all of you "Merry Christmas and Very Happy New year 2011" "Christmas day is a day of Joy and Charity, May God make you rich in both" - Phillips Brooks ## ---------------------------------------------------------------------------------------------------------------------------- I have a process which generates number of outputs. The R code

...than 2 levels with several continuous predictors. The model > being ordinal, I was waiting the glm function to return several intercepts, > which is not the case when looking to my results (I only have one > intercept). I finally managed to perform an ordinal polytomous logisitc > regression with the polr function, which gives several intercepts. > But does anyone know what was the model performed with glm and why only one > intercept was given ? It's not sufficiently clear (to me at least) what you're trying to do. Please pro...