Your review begins with a high-level summary - this helps the audience to quickly grasp the idea of your md file. Very few other students have done this, although this is very helpful.
You used piping to tabulate, subset, and sort the dataset. While this is only taught later in this class, you have tried you best to use what you've learned and keep up with the materials.
Suggestion:
The linear relationship is not obvious and there may be more you might want to explore but didn't have time. Anyways, you have followed the instructions and done what was asked.
Remark:
Suggestion:
Very good job overall!