If you could answer both a and b that’d be great, but you can do only one if you want.

For a, this is just the median and the range of the data. Median is the middle number after all of them are in order, and the range is the highest number minus the smallest number.

If we arrange them all in order:

2, 4, 5, 5, 5, 6, 7, 8, 9, 9, 10, 10, 11, 12, 14, 15

The middle ones are 8 and 9, because there is an even number of results. That means the median is 8.5.

The range is 15 - 2, which is 13.

For b, 21 is an outlier because it is outside the set of movies watched. If 21 was a value in the table, that means that the order is:

2, 4, 5, 5, 5, 6, 7, 8, 9, 9, 10, 10, 11, 12, 14, 15, 21

Meaning that the middle value is now 9 (because of the odd number of values) and the range is 21 - 2, which is 19. The range would increase because the 21 is greater than all the other values (outlier), so the highest number is now 21. The median would also increase because you added a higher number to the list of numbers, so that the middle would shift one place higher.

Hope I helped!