Let’s consider the usual linear regression model, with the full set of assumptions:                     y = Xβ + ε ;    ε ~ N[0 , σ2In] , (1)where X is a non-random (n × k) mat...

I am comparing estimates from subject-specific GLMMs and population-average GEE models as part of a publication I am working on. As part of this, I want to visualize predictions of each type of model including 95% confidence bands. First I had to ma...

Recently a student asked about the difference between confint() and confint.default() functions, both available in the MASS library to calculate confidence intervals from logistic regression models. The following example demonstrates that they yield d...

This is my first blog since joiningR-bloggers. I’m quite excited to be part of this group and apologize if I boreany experienced R users with my basic blogs for learning R or offendprogrammers with my inefficient, sloppy coding. Hopefully writing for...

..an illustrative example for testing proportions and presenting the results.the data: number of indigenous and alien plant species with and without vegetative reproduction. Hypothesis: The proportion of species with vegetative reproduction is differen...

Sigmoid curve fitting for transpiration measurements from porometer at different water potentials (pressure):Read more »

In a recent post, I discussed some  statistical consultancy I was involved with. I was quite proud of the nice ggplot2 graphics I had created. The graphs nicely summarised the main points of the paper: I’ve just had the proofs from the journal, and next to the graphs there ...