R Tutorial - #10 - Planned contrasts

Sections: 0:00 Introduction 1:50 Import the data set (Alcohol and Self-control Study) and create a data frame 2:25 What are "contrasts"? 6:06 Seven Rules for building contrasts 13:57 Contrasts using the aov_4() function 19:53 Contrasts using the lm() function I begin by explaining what a "contrast" is and then detail the so-called 'Seven Rules' for building contrasts. The rest of the tutorial explains how to apply these Seven Rules to the two functions we've been using to run contrasts for a one-way independent ANOVA. First, I explain how to run contrasts using the aov_4() function. Second, I explain how to run contrasts using the lm() function. To freely download the R code and data sets used in this tutorial series, visit http://github.com/Statistics4Doctors. This tutorial analyzes a data set modified from data built by Dr. Andy Field (   / profandyfield  ) for his textbooks on statistics: Discovering Statistics using R (https://tinyurl.com/y6r6wsot) and SPSS (https://edge.sagepub.com/field5e).