9. Two classes, each with 21 students, took a physical fitness test. The number of pull-ups done by each student in 30 seconds was recorded.

(i) Explain why we are unable to calculate the mean number of pull-ups done by the students in each class (ii) Find the median number of pull-ups done by the students in each class.
(iii) State the modal number of pull-ups done by the students in each class.
(iv) Does the median or the mode give a better comparison of the number of pull-ups done by the students in the two classes? Explain your answer.

Number of pull-ups 56 7 8 910 Class A Number of 3 7 4 4 2 1 students Number of 5 6 7 8 9 10 pull-ups Class B Number of 34 4 7 2 1 students