Question

20 plants were measured and their heights recorded in cm.
Here are the heights:
8.5
12.6
13.2
17 11.1
7.7
4.8 9.9 13.5
15.6 17.4
14
12 14.7 9.5
9.8
10
11.3
5 10 15 6.9
5

please answer :
a)
and
b)