I finally reached the point where I was using dplyr enough to get annoyed with typing %>%. I’m guessing if… Read more
Category: Using R
Partial Residuals and the termplot function
Earlier this year I taught an Intro to R Graphics workshop. While preparing for it I came across the termplot… Read more
Permutation Tests
Let's talk about permutation tests and why we might want to do them. First think about the two-sample t-test. The… Read more
Simulating responses from a linear model
Say you fit a model using R's lm() function. What you get in return are coefficients that represent an estimate… Read more
Getting started with GitHub Gist in WordPress
I’ve decided it’s time to use GitHub Gist for posting code snippets in my blog. My original motivation was better… Read more
Exploring Unordered Contrasts in R
Contrasts in R determine how linear model coefficients of categorical variables are interpreted. The default contrast for unordered categorical variables… Read more
Modeling Discontinuous Change (Ch 6 of ALDA)
Chapter 6 of ALDA introduces strategies for fitting models in which individual change is discontinuous. This means the linear trajectory… Read more
Treating Time More Flexibly (Ch 5 of ALDA)
Through 4 chapters of Applied Longitudinal Data Analysis (ALDA), the data sets have had the following constraints: Balanced – all… Read more
A Probability Problem in Heredity – Part 3
In my previous two posts I showed worked solutions to problems 2.5 and 11.7 in Bulmer’s Principles of Statistics, both… Read more
Testing Composite Hypotheses about Fixed Effects (Ch 4 of ALDA)
I’m still on my ALDA kick here, this time posting about section 4.7 of Chapter 4. In my last post… Read more