The three averages on a graph

A football team's goals in 20 matches are in a list. You will find the mode, the mean and the median, and mark all three on a bar chart of the goals. Then you add one freak match with 15 goals and see which averages move.

The idea. The mode is the most common value, the mean is the total over the count, and the median is the middle. An extreme value moves the mean much more than the median.

Your tasks.

1. Set mode to the number of goals that appears most often.
2. Set mean to the total of the goals divided by the number of matches.
3. After the line that adds the 15-goal match, set new_mean and new_median.