This tutorial requires the ggplot2 and the reshape2 packages. Importantly, a past tutorial, ‘Bar Plot with GGPlot’ walks you through what wide and long format data is, so make sure that you have read this information to better understand what we are doing here.
 
Line plots are appealing ways to present continuous data. This can include one or more levels (lines). Here, we will be presenting two lines of data. This tutorial will show you how to make line plots, however, it is formatted for ERP data. Within the script, there are comments that point out where some of the code may be removed if you are not presenting ERP data.
 
Similar to the last tutorial, I will not here walk you through each part of the code. The reason for this is that this code is much more elaborate than what you’ve used before. Instead, I have decided to give you working code which has extensive commenting. I suggest you read the comments thoroughly, but also play around with it. The best way to learn what every line of code does is by playing with it. See what happens if you delete a line, or if you change a value. If you don’t do these things, you will not truly understand what everything does.
 
HERE is the data you will need for this tutorial.
HERE is the code you will need for this tutorial.
 
Now, load the script into R and the tutorial will continue there.