# Calculating the Uncertainty for an Average Value [closed]

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

$32.5 \pm 0.1$

$32.0 \pm 0.1$

$32.3 \pm 0.1$

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

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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 $\sigma \approx 0.20548$