What is the mean deviation of x, 2x, x+1 and 3x. If their mean is 2?
-
0.5
- 1.0
- 1.5
- 2.0
The correct answer is: A
Explanation
| x | ∴x | x-X | /x-X/ |
| x | 1 | -1 | 1 |
| 2x | 2 | 0 | 0 |
| x+1 | 2 | 0 | 0 |
| 3x | 3 | 1 | 1 |
| ∑/x-X/=2 |
| Mean = | x+2x+x+1+3x |
| ____4 |
| 2 = | 7x+1 |
| _4 |
8 = 7x+1
7x = 8-1
7x = 7
x = 1
| Mean deviation = | ∑/x-X/ |
| __n |
| = | 2 |
| 4 |
| = | 1 |
| 2 |
= 0.5
There is an explanation video available .