This is actually a GRE problem, I'm just trying to go through and understand them all for studying purposes, but I don't understand how to do this one at all.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

A student makes 10 one-second measurements of the disintegration of a sample of long-lived radioactive isotope and obtains the following values.

3, 0, 2, 1, 2, 4, 0, 1, 2, 5

How long should the student count to establish the rate to an uncertainty of 1 percent?

2. Relevant equations

I have no idea. But I would guess that standard deviation might be involved..

[tex]\sigma_{x}^{2}=\langle x^{2}\rangle-\langle x\rangle^{2}[/tex]

3. The attempt at a solution

But I am unsure how to get time involved in this. But the standard deviation is 2.4

Any help is appreciated.

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# Uncertainty in measurement (GRE question)

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