An R Companion for the Handbook of Biological Statistics

Salvatore S. Mangiafico

Chapters Not Covered in This Book


Step-by-step analysis of biological data

Types of biological variables


Basic concepts of hypothesis testing

Confounding variables



Data transformations

See the Handbook for information on these topics.


Homoscedasticity and heteroscedasticity

Bartlett’s test is performed with the bartlett.test function.  Levene's test can be invoked with the leveneTest function in the car package.  This test can also be used for a model with two independent variables.  They are used in the chapter on One-way anova.