In RStudio how can I get the average for a score for each category listed - for example, same col has senior and junior and another column shows grades received. How to I get the average for senior and average for junior

In RStudio how can I create a box plot that will show based on on col if senior or junior who did the most extra courses and also out of these two groups which has the most variation Lastly in RStudio how can I calculate the mean, mediam and mode where applicable based on the age, height and readership. Also, how can I measure variation such as variance, standard deviation and IQR?