Test Index

JAMB Mathematics 2019 Paper

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Question : 15

Total: 73

Score (x)	0	1	2	3	4	5	6
Freq (f)	5	7	3	7	11	6	7

Find the variance

3.42
4.69
4.85
3.72

Solution:

x	f	fx	(x - $\overline{x}$ )	(x - $\overline{x}$ ) $^{2}$	f(x - $\overline{x}$ ) $^{2}$
0	5	0	-3.26	10.628	53.14
1	7	7	-2.26	5.108	35.756
2	3	6	-1.26	1.588	4.764
3	7	21	-0.26	0.068	0.476
4	11	44	0.74	0.548	6.028
5	6	30	1.74	3.028	18.168
6	7	42	2.74	7.508	52.556
	46	150			170.888

Variance = $\frac{\sum f(x - \overline{x})}{\sum f}$

= $\frac{170.888}{46}$

= 3.72

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