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Simple stats problem: number of tests to be significant?

  1. Nov 9, 2011 #1
    Hey guys,

    Basically I have a component that I want to test multiple times. The outcome of each test is simply a Pass/Fail. What I want to know is how many tests do I have to do to be (say) 95% sure that I have the right result?

    My stats knowledge is a bit hazy but I know that for these type of yes/no situations it may be possible to use the Binomial distribution. Am I on the right tracks?

    Cheers if you can help.
  2. jcsd
  3. Nov 9, 2011 #2


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    Science Advisor

    This is an idea; I don't know what the real-life constraints you are working with, so here is a general idea: you can use the CLT to estimate the mean: take many random, independent samples (tests, with results of pass/fail, or 1/0) of the same size N: for each sample compute the mean number of sucesses (total successes/total trials). By the CLT, this random variable, the sampling mean, has a normal distribution. Then use a 95% confidence interval about the samplingn mean.
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