95% confidence interval of the mean of a populationsample
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Hi,
Have not been able to locate an answer on this forum to this (seemingly, but for me unsolvable) simple question: how to calculate a 95% confidence interval of the mean of a populationsample, i.e. what is the absolute range of values that fall within 95% of all values.
Jan
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Accepted Answer
Oleg Komarov
on 19 Mar 2011
If the sample follows a particular distribution and you have the stats TB, then you can estimate the parameters with the confidence intervals you want.
Oleg
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More Answers (1)
Germán
on 20 Mar 2011
Another good option, if you have a reasonably "large" data set and dont know the underlying distribution, is to use bootstrap. The function is bootci. Personally, I favor the bca confidence interval because it works on non-normal cases; unimodality is still a requisite though.
Bootstrap is a resampling statistic, it takes your data as an accurate depiction of the population and samples it (with replacement) to estimate the distribution of a particular statistic you are interested in, e.g. the mean.
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Germán
on 20 Mar 2011
Note: since it uses resampling it will vary slightly from call to call (depending on the number of samples; more samples, less variation), so you want to aim for a large number of samples. n >= 1000.
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