similar to: Select some, but not all, variables stepwise

Hola Compañeros, Estoy tratando de "contar" utilizando la función tapply y length y obtengo un error que no entiendo. Agradecería su ayuda. Las líneas son las siguientes: UNO <- subset (datos, CRIH2008 == "VERDADERO") dim (UNO) Abund2008 <- tapply (UNO$Cons, list(UNO$Site, UNO$Trat), length, na.rm=T) Y obtengo este error: Error en FUN(X[[1L]], ...) : 2 arguments

Hola Javier, Muchas gracias por responder tan rápido! Yo trabajo en Mac OS X 10.9.4. Versión 0.98.953 de RStudio. Versión 3.0.2 (2013-09-25) de R. ## Este es el script que estoy trabajando. Se trata de una rutina para automatizar el cálculo de la duración del evento. setwd("/Users/angelacamargosanabria/Documents/ANGELITA/1-DOC/1-TESIS/4-PAPERS/1-Mamiferos/DATOS/Bases") BASE <-

Buenos días a todos, Una pregunta muy sencilla, podrían por favor informarme dónde puedo conocer el significado de símbolos como $, %, == que se utilizan frecuentemente en R? Gracias, Angela C. ---- *Angela Andrea Camargo Sanabria* Estudiante Doctorado en Ciencias Biológicas Laboratorio de Ecología de poblaciones y comunidades tropicales Centro de Investigaciones en Ecosistemas (CIEco) UNAM,

Quisiera intercambiar ideas con aquellos que lo hayan utilizado. Muchas gracias y bonito día! ---- *Angela Andrea Camargo Sanabria* Estudiante Doctorado en Ciencias Biológicas Laboratorio de Ecología de poblaciones y comunidades tropicales Centro de Investigaciones en Ecosistemas (CIEco) UNAM, campus Morelia Antigua Carretera a Pátzcuaro # 8701 Col. Ex-Hacienda de San José de la Huerta, CP 58190

Hola a todos, Por casualidad alguno que tenga el libro de Legendre de Numerical Ecology with R sabe dónde o cómo bajar los data sets que se mencionan para seguir los ejemplos? Muchas gracias por su ayuda! ---- *Angela Andrea Camargo Sanabria* Estudiante Doctorado en Ciencias Biológicas Laboratorio de Ecología de poblaciones y comunidades tropicales Centro de Investigaciones en Ecosistemas

Hola a todos, Escribo para preguntarles sobre cómo programar algo, que estoy segura es algo bastante sencillo para muchos de Uds que tienen amplia experiencia programando. Lo describo a continuación. Tengo una base de datos (file = datos) de especies (de plantas) en donde cada fila es un individuo de una especie con ciertos atributos (alrededor de 1500 filas = individuos). Quería anexar en esta

Hola a todos, Tengo la siguiente inquietud, espero me puedan ayudar. Tengo una base de datos de la que estoy haciendo varios cálculos. Uno de ellos es la diferencia entre tiempos para conocer la duración de un evento. Aquí usé el paquete lubridate para tener fecha y hora en el formato adecuado. Cuando hago el calculo obtengo algo como esto: > (BASE$Time2[518]-BASE$Time2[516]) Time difference

Dear R users, I am using lme and nlme to account for spatially correlated errors as random effects. My basic question is about being able to correct F, p, R2 and parameters of models that do not take into account the nature of such errors using gls, glm or nlm and replace them for new F, p, R2 and parameters using lme and nlme as random effects. I am studying distribution patterns of 50 tree

Hi all I?m trying to tests the significance of loadings from a ordination of 46 variables (caategorical, ordinal and nominal). I used dudi.mix from ade4 for the ordination. A years ago Jari Oksanen wrote this script implementing Peres-Neto et al. 2003 (Ecology) bootstraping method: netoboot <- function (x, permutations=1000, ...) { pcnull <- princomp(x, cor = TRUE, ...) res

oops, Forgot to cc to the list. Regards, Mike -----Original Message----- From: dr mike [mailto:dr.mike at ntlworld.com] Sent: 24 February 2005 19:21 To: 'Spencer Graves' Subject: RE: [R] Bayesian stepwise (was: Forward Stepwise regression based onpartial F test) Spencer, Obviously the problem is one of supersaturation. In view of that, are you aware of the following? A Two-Stage

Hola Angela, yo tambien he usado la funcion "rarecurve" para crear curvas de rarefacción Saludos Gabriel Antonio Trujillo Paucar Egresado de Biologia - Especialidad de Ecología Investigador en el Area de Limnología de CORBIDI 997603768 ---------------------------------------- > From: r-help-es-request en r-project.org > Subject: Resumen de R-help-es, Vol 48, Envío 13 > To:

Dear R, I am using stepwise multiple glm to select a subset of variables using the step command. My question is how do you calculate the percentage variance for each parameter in the reduced model. An example of my code thus far is, fit<-glm(Abalone~offset(Area)+Sessile invertebrates+Bare rock+ NCA + Encrusting red algae, family = poisson ()) step(fit) fit1<-glm(Abalone~offset(Area)+Bare

I need to do a classic stepwise regression based not on AIC but on F in and F out (or on R2, or R2 adjusted). I have many variables and it will very useful for me to have a fast stepwise algorithm. Does anyone know if this exists for R and where I can find that ? Thank you very much. Pascal Grandeau -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing

Hi All, I am looking for a package that performs Repeated k-fold cross-validation with Stepwise Regression. I would greatly appreciate if someone could share with us a package(s) that include this type of analysis. Thank you very much in advance. Chris [[alternative HTML version deleted]]

I have a question regarding doing forward stepwise regression using the step function and an lm model. I am trying to run a stepwise procedure that will add a predictor variable, one at a time, conduct an F test to determine whether or not to drop any previous terms, and terminate when no other predictors qualify to be added. Using the step function and looking at the example in the book, I

Dear Gurus, Thank you in advance for your assistance. I'm trying to understand scope better when performing stepwise regression using "step." I have a model with a binary response variable and 10 predictor variables. When I perform stepwise regression I define scope=.^2 to allow interactions between all terms. But I am missing something. When I perform stepwise regression (both

I am using VEGAN ordistep function for stepwise model selection. By default the Pin and Pout values are set to .05 and .1 Is it appropriate to use a family wise correction ( such as bonferroni or one of the alternatives) to adjust these values where there are several (5-10), potentially correlated variables in the model selection process? -- Nevil Amos Molecular Ecology Research Group

I'm looking for guidance on how to implement forward stepwise regression using lmStepAIC in Caret. The stepwise "direction" appears to default to "backward". When I try to use "scope" to provide a lower and upper model, Caret still seems to default to "backward". Any thoughts on how I can make this work? Here is what I tried: itemonly <-

Hello all, I have a question on manova in R: I'm using the function "manova()" from the stats package. Is there anything like a stepwise (backward or forward) manova in R (like there is for regression and anova). When I enter: step(Model1, data=Mydata) R returns the message: Error in drop1.mlm(fit, scope$drop, scale = scale, trace = trace, k = k, : no 'drop1'

Hello, I am interested in performing a stepwise regression using the robust regression technique to estimate the models at each stage. At the moment I am using the lm code and the stepAIC code to select the "best" OLS model. This final model is then re-estimated using the rlm code. I am hoping there is a better was to do this, where at each step of the "stepwise" code the