Calculating the Uncertainty for an Average Value [closed]

How would I calculate the uncertainty for the average of this set?

$32.5 \pm 0.1$

$32.0 \pm 0.1$

$32.3 \pm 0.1$

-

closed as off topic by Colin K, David Z♦Sep 3 '12 at 18:35

Questions on Physics Stack Exchange are expected to relate to physics within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here. If this question can be reworded to fit the rules in the help center, please edit the question.

Would someone please fix the formatting? –  Nyx Jun 9 '12 at 17:40

The standart deviation $\sigma=\sqrt{\frac{\sum_{i=1}^n a_i^2}{n}-\left(\frac{\sum_{i=1}^n a_i}{n}\right)^2}$, where $a_i$ is the $i$-th number in your set and $n$ is the number of numbers you have in your set (in your example $a_1=32.5$, $a_2=32.0$, $a_3=32.3$ so $n=3$)
Using the numbers from your question I got $\sigma \approx 0.20548$