11. Find the mode of the following data

a)

8

5 2 3 3 5 3 1

b)

19

18 17 16 17 15 14 15 15 9

12. The following are the scores (out of 100 items) of 16 students in a diagnostic test in Statistics.

91 89 89 88 88 87 89 91 86 85 86 87 92 81 87 85

Find the modal score.