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
A Probability Problem in Heredity – Part 2
In my last post I solved a problem from chapter 2 of M.G. Bulmer’s Principles of Statistics. In this post… Read more
A Probability Problem in Heredity
Here’s a fun problem in heredity from the Dover classic Principles of Statistics by M.G. Bulmer. It’s from chapter 2,… 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
Comparing Multilevel Models using Deviance Statistics (Ch 4 of ALDA)
The tour of Applied Longitudinal Data Analysis (ALDA) by Singer and Willett continues today with section 4.6, Comparing Models using… Read more
Unconditional Multilevel Models for Change (Ch 4 of ALDA)
In Chapter 4 (section 4.4) of Applied Longitudinal Data Analysis (ALDA), Singer and Willett recommend fitting two simple unconditional models… Read more
The Multilevel Model for Change (Ch 3 of ALDA) – revisited
In my previous post I talked about how to replicate the example in Chapter 3 of ALDA. It was mostly… Read more