R: Recipes for Analysis, Visualization and Machine Learning

Working with Pearson's Chi-squared test

In this recipe, we introduce Pearson's Chi-squared test, which is used to examine whether the distributions of categorical variables of two groups differ. We will discuss how to conduct Pearson's Chi-squared Test in R.

Getting ready

Ensure that mtcars has already been loaded into a data frame within an R session. Since the chisq.test function is originated from the stats? package, make sure the library, stats, is loaded.

How to do it

Perform the following steps:

1. To make the counting table, we first use the contingency table built with the inputs of the transmission type and number of forward gears:

   > ftable = table(mtcars$am, mtcars$gear)
   > ftable
      
        3  4  5
     0 15  4  0
     1  0  8  5
   

2. We then plot the mosaic plot of the ...