Answer:
Frequency means the number of times the value occurs in the data set.
Therefore, to determine the frequency of height 63, count the number of times "63" occurs in the data set. From inspection of the data set, we can see that there are five "63"s so the frequency of 63 is 5.
Height Frequency
63 5
64 1
65 6
66 2
67 3
68 3
69 4
70 0
71 2
72 4
Total 30
