waecE-LEARNING
General Mathematics Paper 2,May/June. 2012  
Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 Main
General Comments
Weakness/Remedies
Strength













Question 10

         

Class interval

Frequency

60 – 64
65 – 69
70 – 74
75 – 79
80 – 84
85 – 89
90 – 94
95 - 99

2
3
6
11
8
7
2
1

 

The table shows the distribution of marks scored by students in an examination.
Calculate, correct to 2 decimal places, the
(a)      mean;
(b)     standard deviation of the distribution.


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Observation

The Chief Examiner reported that this question was attempted by majority of the candidates and they performed very well in it.  Candidates were reported to have drawn the appropriate table and applied the appropriate formulae to obtain the required results. Candidates were expected to draw the following table.

Class Interval

f

Class Mid-point x

fx

fx2

60 – 64

2

62

124

7688

65 – 69

3

67

201

13467

70 – 74

6

72

432

31104

75 – 79

11

77

847

65219

80 – 84

8

82

656

53792

85 – 89

7

87

609

52983

90 – 94

2

92

184

16928

95 – 99

1

97

97

9409

 

Σf = 40

 

Σf = 3150

Σfx2 = 250,590

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