After Lecture 3 you should complete the following swirl lessons in the Exploratory Data Analysis course:
Before starting this swirl course you should install a few packages by taking these steps:
install.packages("Rcpp")
.Do you want to install from sources the package which needs compilation?
. Type n
into the R console and then press enter.install.packages(file.choose(), repos = NULL, type="source")
and select the file you just downloaded.install.packages("jpeg")
.You should now have no problems with the lessons in the Exploratory Data Analysis course.