The scores of some students in a class test are 4, 6, 1, 8, 9, 5, and 2. Calculate, correct to one decimal place, the mean deviation of their scores.
-
2.3
- 2.7
- 5.0
- 5.2
The correct answer is: A
Explanation
The scores of some students in a class test are 4, 6, 1, 8, 9, 5, and 2
M.D = \(\frac{\sum {|x - \overline{x}|}}{n}\)
\(\overline{x}\) = \(\frac{4 + 6 + 1 + 8 + 9 + 5 + 2}{7}\) = \(\frac{35}{7}\) = 5
| x | x - \(\overline{x}\) |
|x - \(\overline{x}\)| |
| 4 | 4 - 5 = - 1 | 1 |
| 6 | 6 - 5 = 1 | 1 |
| 1 | 1 - 5 = - 4 | 4 |
| 8 | 8 - 5 = 3 | 3 |
| 9 | 9 - 5 = 4 | 4 |
| 5 | 5 - 5 = 0 | 0 |
| 2 | 2 - 5 = - 3 | 3 |
\(\sum {|x - \overline{x}|}\) = 16
M.D = \(\frac{\sum {|x - \overline{x}|}}{n}\) = \(\frac{16}{7}\) = 2.2857 β 2.3