From the prices of shares X and Y below, find out which is more stable in value:
| X | 35 | 54 | 52 | 53 | 56 | 58 | 52 | 50 | 51 | 49 |
| Y | 108 | 107 | 105 | 105 | 106 | 107 | 104 | 103 | 104 | 101 |
The prices of the shares X are
35, 54, 52, 53, 56, 58, 52, 50, 51, 49
Here, the number of observations, N = 10
The following table is obtained corresponding to shares X.
| xi |
|
|
| 35 | –16 | 256 |
| 54 | 3 | 9 |
| 52 | 1 | 1 |
| 53 | 2 | 4 |
| 56 | 5 | 25 |
| 58 | 7 | 49 |
| 52 | 1 | 1 |
| 50 | –1 | 1 |
| 51 | 0 | 0 |
| 49 | –2 | 4 |
| 350 |
The prices of share Y are
108, 107, 105, 105, 106, 107, 104, 103, 104, 101
The following table is obtained corresponding to shares Y.
| yi |
|
|
| 108 | 3 | 9 |
| 107 | 2 | 4 |
| 105 | 0 | 0 |
| 105 | 0 | 0 |
| 106 | 1 | 1 |
| 107 | 2 | 4 |
| 104 | –1 | 1 |
| 103 | –2 | 4 |
| 104 | –1 | 1 |
| 101 | –4 | 16 |
| 40 |
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C.V. of prices of shares X is greater than the C.V. of prices of shares Y.
Thus, the prices of shares Y are more stable than the prices of shares X.