Week 4: Multiple Linear Regression

January 29-30, 2018

The logic behind multiple linear regression is similar to that of simple regression. This week we will look at what happens when you regress more than one covariate against Y.

We will focus on running and interpreting these models, but will not look at assessing their fit just yet. (We will save that for Week 5).

Lecture Topics

  • The basic structure of a general linear model
  • How to interpret beta values for categorical and continuous covariates
  • Interation terms
  • Specifying models in lm()

In-class Activities

Part 1 will involve some relatively simple code, but perhaps complicated concepts. Part 2 will be more hands-on, and there will be a larger exercise as we work on the data from the lionfish paper below.

Pre-class Prep


In Part 1, we will look at urchin data from the paper we worked on in week 2. In Part 2, we will use data from the paper below:

Peiffer F, Bejarano S, Palavicini de Witte G, Wild C. (2017) Ongoing removals of invasive lionfish in Honduras and their effect on native Caribbean prey fishes. PeerJ 5:e3818 https://doi.org/10.7717/peerj.3818

You may read if interested.


Note: This only contains Part 1 content as of Jan 26. Will update with Part 2 by end of day Jan 29.


Part 1 slides via speakerdeck

Part 2 slides via speakerdeck