R session information

The R session information when compiling this book is shown below:

## R version 3.5.2 (2018-12-20)
## Platform: x86_64-pc-linux-gnu (64-bit)
## Running under: Ubuntu 19.04
## 
## Locale:
##   LC_CTYPE=en_US.UTF-8      
##   LC_NUMERIC=C              
##   LC_TIME=en_US.UTF-8       
##   LC_COLLATE=en_US.UTF-8    
##   LC_MONETARY=en_US.UTF-8   
##   LC_MESSAGES=en_US.UTF-8   
##   LC_PAPER=en_US.UTF-8      
##   LC_NAME=C                 
##   LC_ADDRESS=C              
##   LC_TELEPHONE=C            
##   LC_MEASUREMENT=en_US.UTF-8
##   LC_IDENTIFICATION=C       
## 
## Package version:
##   bookdown_0.21    dplyr_1.0.2      ggplot2_3.3.2   
##   infer_0.5.3      kableExtra_1.2.1 knitr_1.30      
##   readr_1.3.1      rmarkdown_2.5    tinytex_0.26    
## 
## Pandoc version: 2.3.1