*Bounty: 50*

*Bounty: 50*

I run a calculation to obtain a value P.

In order to get some kind of idea about the uncertainty the calculation, I created 5,000 sets of simulated data and tried to find a value P for each one of them.

The results were that the mean value of P for the 5,000 tests was:

```
20.0403995664%
```

The standard deviation was:

```
0.695151163704%
```

I just want to be sure of the correct way to quote these values.

Should it be:

```
20.04 +/- 0.70 %
```

or

```
20 +/- 1 %
```

or maybe something else?

I’ve never quite understood this. Is it a matter of opinion or is there a correct way?

If you could provide reasoning along with the answer that would be great, thank you.