similar to: How to optimize or build a better random forest?

Greetings, I am working in the sem package on a model with 3 exogenous variables (2 are nominal-categorical), and 4 endogenous, continuous variables. To use sem with the nominal variables, I created dummy variables. Now, in my sem output I have estimates for path coefficients for the relationship between each level of the nominal variables and the endogenous variables they are associated

Dear R users, I am using lmer combined with AIC model selection and averaging (in the MuMIn package) to try and assess how isotope values (which indicate diet) vary within a population of animals. I have multiple measures from individuals (variable 'Tattoo') and multiple individuals within social groups within 4 locations (A, B, C ,D) crucially I am interested if there are

Hi I would really appreciate some help with my code for coxme... My data set I'm interested in survival of animals after an experiment with 4 treatments, which was performed on males and females. I also have two random factors: Response variable: survival (death) Factor 1: treatment (4 levels) Factor 2: sex (male / female) Random effects 1: person nested within day (2 people did

Hello R experts I have two linear regressions for sexes (Male, Female, Unknown). All have a good correlation between body length (response variable) and head length (explanatory variable). I know it is not recommended, but for a good practical reason (the purpose of study is to find a single conversion factor from head length to body length), the regressions need to go through the origin (0

Hello All, I cant seem to do a trig regression in R. The equation is as follows : y = a+b*(sin((2*pi*x/360) - c))^2 a, b, c are coefs that I want. y, x are input vectors. The equation I put into R: lm(y ~ sin(2*pi*x/360)^2) This equation is missing the c and I dont get the right answer. Also, I dont know how to plot the lm over the x values instead of the indices. Any help is sincerely

Hello all, I recently installed rpy2 so that I could use R through Python. However, R was not recognized in the command line. So I decided to add it to the PATH variables. But it just doesnt work.... And what I mean by it doesnt work is : No matter what I type at the prompt in DOS- be it R, Rcmd, R CMD, Rscript- it is not recognized as a command. Path variables used : 1. %R_HOME% -->

Am I correct in assuming that the output below essentially translates to "Males have a mean time that is significantly lower than Females"? Is this the correct way to interpret the fact that the coefficient is negative? Assume the variale sex is treated as a factor with Female =0 and Male=1. survmodel<-survreg(survobj~sex,data=data1, dist="weibull")

Hello All, Does anyone know how to download historical LIBOR rates of different currencies into R? Or if anyone knows of a website that holds all this data...I only need up to january of 2000. Also, how can we make the row names the index of a plot (the names of the x values)? [[alternative HTML version deleted]]

Hi, here are three results of random forest (version 4.0-1). The results seem to be more or less the same which is strange because I changed the classwt. I hoped that for example classwt=c(0.45,0.1,0.45) would result in fewer cases classified as class 2. Did I understand something wrong? Christian x1rf <- randomForest(x=as.data.frame(mfilters[cvtrain,]),

Hi, I have a problem with the time formatting in R. I have entered time in the format "MM:SS.xyz" and R has automatically classified this as a factor, but I need it numerically. However when I use as.numeric() it gives me totally different numbers. Is there any way I can tell R to read thes input as a number? Thank you very much [[alternative HTML version deleted]]

Hi, I am trying to model a dataset with the response variable Y, which has 6 levels { Great, Greater, Greatest, Weak, Weaker, Weakest}, and predictor variables X, with continuous and factor variables using random forests in R. The variable Y acts like an ordinal variable, but I recoded it as factor variable. I ran a simulation and got OOB estimate of error rate 60%. I validated against some

Hi All, I am looking for a reference that explains how the randomForest function in the randomForest package uses the classwt parameter. Here: http://tolstoy.newcastle.edu.au/R/e4/help/08/05/12088.html Andy Liaw suggests not using classwt. And according to: http://r.789695.n4.nabble.com/R-help-with-RandomForest-classwt-option-td817149.html it has "not been implemented" as of 2007.

Guys, I wrote to the finance mailing list earlier with my questions but was directed here. Sorry for the repeat. --------------- library(quantmod) .... now <- Sys.time() midnight <- strptime() # <---- I want to make this a static variable that will be equal to 12:00:00 am but I dont know what to put here. I keep getting NA for everything I do if(now == midnight) {

Hey everyone, I hope this finds you in good cheer. I just have a quick question: What is the function that outputs the p-value for correlation? cor(x,y) only provides the R value. I would like the p-value associated with it. Thank you all for your help! [[alternative HTML version deleted]]

"classwt" in the current version of the randomForest package doesn't work too well. (It's what was in version 3.x of the original Fortran code by Breiman and Cutler, not the one in the new Fortran code.) I'd advise against using it. "sampsize" and "strata" can be use in conjunction. If "strata" is not specified, the class labels will be used.

I have a process where I am creating a effects plot similar to the cowles effect example. I would like to add the point estimates to the effects plot, can someone show me the correct syntax. I have included the "R" effects example, so you can show me the correct syntax. Thanks mod.cowles <- glm(volunteer ~ sex + neuroticism*extraversion, data=Cowles, family=binomial)

Sorry for the repost, but I've really been looking, and can't find any syntax direction on this issue... Just browsing the documentation, and searching the list came up short... I have some unbalanced data and was wondering if, in a "0" v "1" classification forest, some combo of these options might yield better predictions when the proportion of one class is low (less

Just browsing the documentation, and searching the list came up short... I have some unbalance data and was wondering if, in a "0" v "1" classification forest, if these options might yield better predictions when the proportion of one class is low (less than 10% in a sample of 2,000 observations). Not sure how to specify these terms... from the docs, we have: classwt: Priors

Dear list members, I fitted a glm model (See output below). My outcome is death, and weight (continuous), ClutchSize (3-level factor), EggVolume (continuous), Sex (obviously 2-level factor), and SiblingCompetence (2-level factor) are my covariates. I'd like to obtain the odds of death for a range of Weights, EggVolumes, and different combinations of ClutchSize. I've tried using the

Hello there, I am working on an extremely unbalanced two class classification problems. I wanna use "classwt" with "down sampling" together. By checking the rfNews() in R, it looks that classwt is not working yet. Then I looked at the software from Salford. I did not find the down sampling option. I am wondering if you have any experience to deal with this problem. Do you