# What's the difference between (sample) standard deviation and absolute uncertainty?

So I was calculating the sample standard deviation values for 5 trials and I noticed that the values were really close to the absolute uncertainty of the mean found using the formula: (max - min)/2

Are they the same thing? If I want to plot error bars on a graph, could I use the standard deviation values instead of the absolute uncertainty values since they are basically the same (according to me)?

• I've never seen (max-min)/2 called the "absolute uncertainty of the mean". That formula doesn't compute anything about the mean at all, nor is it any kind of measure of uncertainty. It's simply the range divided by 2. Feb 18, 2021 at 18:25
• @NuclearHoagie - Could you help me understand the difference between “uncertainty in a measurement” and “uncertainty in the mean” on page 4 of this document? Feb 18, 2021 at 18:31
• Range/2 makes more sense as an uncertainty measure in the context of repeated measurement on the same sample (not sure if that's the case here), like if you measure someone's height 5 times. This give a sense of how precise/uncertain your measurement tool/technique is. The uncertainty in the mean, on the other hand, usually goes down as you take more measurements, since positive and negative errors will average out and more data gives you less uncertainty. Feb 18, 2021 at 18:44