search for: christian_mora

Hi: I have data from an assay in the form of two vectors, one is response and the other is a predictor. When I attempt to fit a 5 parameter logistic model with "nls", I get converged parameter estimates. I also get the same answers with "gnls" without specifying the "weights" argument. However, when I attempt to use the "gnls" function and try to

Hi all, I?m working with a dataset with 9 columns and 2000 rows. Each row represents an individual and one of the columns represents the volume of that individual (measured in cubic meters). I?d like to select a sample from this dataset (without considering any probability of the rows) in which the sum of the volume of the individuals in that sample >= 100 cubic m. I?ll appreciate any

Hi all; I?m working with the latest version of R under Win2000. My internet connection (using a proxy) requires my username and password. In this situation I?m not able to update the packages from CRAN (unless I download and install them from a local drive). I tried looking at information on the list servers but I couldn?t figure out how to change 'environment variables' or something like

Dear R users; Ive got two questions concerning nlme library 3.1-65 (running on R 2.2.0 / Win XP Pro). The first one is related to augPred function. Ive been working with a nonlinear mixed model with no problems so far. However, when the parameters of the model are specified in terms of some other covariates, say treatment (i.e. phi1~trt1+trt2, etc) the augPred function give me the following

Dear R users; I'm trying to fit nonlinear model (asymptotic regression model) with gnls from library nlme in R 2.1.0 with no big issues so far. However after installed the version R 2.1.1, when I tried to update the initial model including a var-cov model I've got the error: "Error: Object "convIter" not found". This error occurs only with R 2.1.1. Any ideas? Thanks

Hi all; I'm working with the library SuppDists trying to fit a Johnson's Sb distribution to a dataset. It works fine, but I need to set one of the location parameters (epsilon) to zero. How can I do this using the function JohnsonFit() or any other similar? ...and Is it possible to define the type (SN,SL,SB,SU) or the library assumes the type automatically depending on the data? Thanks

Hi all; Im working with two datasets in R, say data1 and data2. Both datasets are composed of several rows and columns (dataframe) and some of the rows are identical in both datasets. Im wondering if there is any way to remove from one set, say data1, the rows that are identical in the other set, say data2, using R? Thanks for any hint in advance Christian