Let's start by opening a new R-script (select from the top-menu in RStudio: File/New/R Script). This will open a blank document above the console. As you go along you can copy-paste code examples and enter your answers to exercises into this script. This is a good way to keep track of your code and be able to reuse it later. To run your code from your script put your cursor on the line (or select a code-block) to be executed and hit command+enter (Mac) or control+enter (PC).

Execute the following command in R to load the hybrid dataset:

source("http://horizon.science.uva.nl/public/VVA/hybrid_reg.R")

If everything went well, an object hybrid should have been loaded in the global environment. You can check this in the upper-right pane of RStudio (in the Environment Tab).

Explore the dataset using the following functions that you have learned before (e.g. summary(), str(), head(), class(), dim(), names()).

How many observations does the dataset contain?