The data shows the marks obtained by students in a biology test
52
56
25
56
68
73
66
64
56
48
20
39
9
50
46
54
54
40
50
96
36
44
18
97
65
21
60
44
54
32
92
49
37
94
72
88
89
35
59
34
15
88
53
16
84
52
72
46
60
42
(a) Construct a frequency distribution table using the class interval 0 - 9, 10 - 19, 19, 20, 29...
(b) Draw a cumulative frequency curve for the distribution
(c) Use the graph to estimate the;
(i) median
(ii) Percentage of students who scored at least 66 marks, correct to the nearest whole number.
Verified Correct Answer: .
Step-by-Step Mathematical Solution
Class
Intervals
Class
Boundaries
Frequency
Cumulative
Frequency
0 - 9
0.5 - 9.5
1
1
10 - 19
9.5 - 19.5
3
4
20 - 29
19.5 - 29.5
3
7
30 - 39
29.5 - 39.5
6
13
40 - 4921
39.5 - 49.5
8
21
50 - 59
49.5 - 59.5
12
33
60 - 69
59.5 - 69.5
6
39
70 - 79
69.5 - 79.5
3
42
80 - 89
79.5 - 89.5
4
46
90 - 99
89.5 - 99.5
4
50
\(\sum f = 50\)
(b)
(c) (I) Mean mark = 49.9
(ii) Percentage of at least 66 mark = \(\frac{13}{50} \times 100\)%
= 26%
Source: Myschool Past Questions Archive (Record #58053)