This table below gives the scores of a group of students in a Further Mathematics Test.
| Score | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Frequency | 4 | 6 | 8 | 4 | 10 | 6 | 2 |
Calculate the mean deviation for the distribution
A. 4.32
B. 2.81
C. 1.51
D. 3.90
Correct Answer: C
Explanation
| Score(x) | 1 | 2 | 3 | 4 | 5 | 6 | 7 | Total |
| Frequency (f) | 4 | 6 | 8 | 4 | 10 | 6 | 2 | 40 |
| fx | 4 | 12 | 24 | 16 | 50 | 36 | 14 | 156 |
| x - \(\bar{x}\) | -2.9 | -1.9 | -0.9 | 0.1 | 1.1 | 2.1 | 3.1 | Â |
| |x - \(\bar{x}\)| | 2.9 | 1.9 | 0.9 | 0.1 | 1.1 | 2.1 | 3.1 | Â |
| f|x - \(\bar{x}\)| | 11.6 | 11.4 | 7.2 | 0.4 | 11 | 12.6 | 6.2 | 60.4 |
Mean = \(\frac{\sum fx}{\sum f}\)
= \(\frac{156}{40}\)
= 3.9
M.D = \(\frac{\sum f|x - \bar{x}|}{\sum f}\)
= \(\frac{60.4}{40}\)
= 1.51
