Mean is 9.1 which is the sum of all data (91) divided by the amount of data (10 items). The range is smallest to largest: 2 to 15, which is a range of 13.
We need to calculate the difference from the mean of each value in the dataset. Then we need to square it. The sum of the squares divided by 10 is the variance.
| X |
X-µ |
(X-µ)^2 |
| 2 |
-7.1 |
50.41 |
| 9 |
-0.1 |
0.01 |
| 15 |
5.9 |
34.81 |
| 5 |
-4.1 |
16.81 |
| 15 |
5.9 |
34.81 |
| 10 |
0.9 |
0.81 |
| 13 |
3.9 |
15.21 |
| 10 |
0.9 |
0.81 |
| 4 |
-5.1 |
26.01 |
| 8 |
-1.1 |
1.21 |
The variance is 18.09 so the standard deviation is the square root of this=4.25.