This lesson assumes you have the R, RStudio software installed on your computer.
R can be downloaded here.
RStudio is an environment for developing using R. It can be downloaded here. You will need the Desktop version for your computer.
Install R by downloading and running this .exe file from CRAN. Also, please install the RStudio IDE. Note that if you have separate user and admin accounts, you should run the installers as administrator (right-click on .exe file and select "Run as administrator" instead of double-clicking). Otherwise problems may occur later, for example when installing R packages.