Maybe you wanted to be more explicit by going step by step, but in exercise number 2 you could have used the "droplevels" function since the very beginning (with %>%) when you first filtered the dataset.
In the plot for exercise 2 you could have added a "$" sign to the y axis.
I like how you played with GDP by showing the top 5 countries, it is actually an interesting plot. Also when comparing to the website that you linked that has more recent data, one can notice that India and Germany have switched places.
I like how you changed your plots from previous assignments, they are now more informative. The table where you specified the changes was also useful.
I learned another way to convert "continent" to factor.
Peer-Review HW-05 for Qi Yang
Remarks: