The table gives the distribution of marks for 360 candidates who sat for an examination.
Marks (%) |
0-9 |
10 - 19 |
20 - 29 |
30 -39 |
40 - 49 |
50 - 59 |
60 - 69 |
70 -79 |
80 -89 |
Number of |
20 |
48 |
60 |
72 |
80 |
40 |
25 |
10 |
5 |
candidates |
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(a) Draw a cumulative frequency curve for the distribution.
(b) Use your graph to estimate the semi-interquartile range.
(c) If the minimum mark for distinction is 75%, how many candidates passed with
distinction?