Calculating Uncertainty for Radioactive Isotope Measurements

[dimensionless]

Let's say that I have a long lived radio active isotope and I make 10 one second measurements of the disintegration. My measurements are as follows:

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

How many one second measurements would I have to make to get an uncertainty of 1%?

The answer is 5,000, but I have no idea how to get it.

 

[jim mcnamara]

I'm not sure what you mean but the margin_of_error which sometimes is called the uncertainty can be calculated knowing only the number of observations. 1 divided by the square root of the number of observations.

for 5000 it is about 1.4% which is 1 / sqrt( 5000 )