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I'm working on a problem involving electrical signals which have components which appear to be decaying exponentially.

I think my problem is analogous to radio-active decay. I would like to find the probability that there are N particles remaining after K half-lives. To clarify, for example if a population started out with 100 particles and a half-life of 1 hour, what is the probability that after 2 hours there were 60 particles remaining?

I started out looking at the exponential and binomial distributions but I don't think they're what I'm looking for. Any suggestions would be gratefully received.

Thanks,

James

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# Radio-active decay: probability of N particles after K halflives?

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