The frequency distribution of the weight of 100 participants in a high jump competition is as shown below :
Weight (kg)
20 - 29
30 - 39
40 - 49
50 - 59
60 - 69
70 - 79
Number of Participants
10
18
22
25
16
9
(a) Construct the cumulative frequency table. (b) Draw the cumulative frequency curve. (c) From the curve, estimate the : (i) median ; (ii) semi- interquartile range ; (iii) probability that a participant chosen at random weighs at least 60 kg.
Explanation
(a)
ClassIntervals
freq
cumfreq
classboundaries
20 - 29
10
10
19.5 - 29.5
30 - 39
18
28
29.5 - 39.5
40 - 49
22
50
39.5 - 49.5
50 - 59
25
75
49.5 - 59.5
60 - 69
16
91
59.5 - 69.5
70 - 79
9
100
69.5 - 79.5
(b) (c) (i) Median () = 49.5 (ii) Semi- Interquartile range = ; . Semi- Interquartile range = = = 10.5. (iii) Pr(
