Recent content by jpkelley

  1. jpkelley

    Variation in inflection point for modeled logistic curve

    Hey all. Question category: R and regression; Posted in R forum since R code. Question: How best to quantify variation in an inflection point for a logistic curve? Background of problem: Birdies begin their birdie lives contained in eggs. Then, they hatch and continue their lives...
  2. jpkelley

    [R graphics export/import] High-res graphics from R into Word

    Hi all, I'm completing graphs for my dissertation, and I decided to bite the bullet and ask all of you gurus about how to efficiently export R graphics into Word (no, I'm not using Latex yet). By export into Word, I simply mean export the high-res image into a folder for eventual import into...
  3. jpkelley

    Error detection when using package "plyr"

    Problem: I'm running a custom function on subsets of a data.frame using the dlply function in Wickham's package "plyr." It threw an error related to the ID variable (on which the subsetting is based), and I've been trying to figure out which of the IDs is causing the issue. I added the...
  4. jpkelley

    Graphic placement via locator() in R

    Hi all, I know the likelihood of such a feature is abysmally low, but does anyone know of a package in R that allows creation of composite images via the locator() function? I'm final with viewport and facet capabilities, but I'm curious if I can create irregularly (i.e. non-grid) arranged...
  5. jpkelley

    GLLAMM in R

    Hi all, I seem to recall that some of you (spunky, Dason, and other) might be doing research using latent variable models and their variants. As I start to ask more questions about the temporal sequences of signaling, aggression, and courtship in my experiments on birds (and now spiders)...
  6. jpkelley

    Post-hoc tests in lmer() R

    Hi all, I'll try to make this my last question of the week. Hard to do this, of course, when everyone is so helpful. This is a Q for those somewhat familiar with GLMMs in R, as implemented by lmer() in the "lme4" package. I'm well aware of the fact the reported p-values are generally to...
  7. jpkelley

    Data visualization poll

    Hi, Originally, I thought this might be appropriate for the R thread, but I think this may have more general relevance. I'm trying to decide on a data visualization option, and my right and left sides of my brain are at war. In brief, I've modeled predator densities at two sites (in a...
  8. jpkelley

    Analysis Workflow: Best practices

    Hello all, I hope this finds everyone doing well. I have a couple of questions about workflow for analyses. Hopefully, this will be of broad interest. For each of multiple analyses within multiple projects, I have been using a simple workflow structure consisting of the following...
  9. jpkelley

    Constrained linear regression in R

    Hi all, Using R, I'm running a linear regression for part of a function I'm writing to calculate survival rates from age distributions. My question for the purpose of this thread is following. Given the following sample data set: set.seed(100) fake.data <- data.frame(x=seq(1:20), y=rnorm(20...