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  1. #1
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    sample size calculator




    We want to take a sample out of 500 (population) hospitals. We don't mind having an error of 5%. What is the methodology to calculate sample size? Especially, I don't understand that confidence interval of 5% or 10%. When we have already given confidence level in the calculation, why should one we confidence interval
    Last edited by Dr.Appalayya; 10-15-2008 at 12:11 AM.

  2. #2
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    uhhmm.........5% or 10% confidence interval is not valid since what is the point in selecting the sample if you're only 5% confident that it can really measure what you intend to measure......

    it's 5% margin of error that you are saying.....

    The other question as to what are the methodologies of getting a sample size the more common would be the Sloven's Formula just look it up in the internet ^^

    and btw there are some sites that automatically solves your sample size problems though I forgot the name my bad..........

  3. #3
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    I can suggest the Power and Sample Size program from the Vanderbilt University (http://biostat.mc.vanderbilt.edu/twi...owerSampleSize). It is very easy to use.
    You must know the probability of exposure in controls and the Odds ratio to calculate your sample size

  4. #4
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    What do you try to measure? Is it a proportion? Try this calculator:

    http://www.dimensionresearch.com/res...mple_size.html

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