Calculation of the size of a sample the the size of the population is unknown.

I am working with a colleague to produce a function to determine how frequently a widget should be pulled from a production line and evaluated for quality assurance. My colleague offered Cochran’s Sample Size Formula. This is very much a work in progress.

Z is the confidence level,
p is the probability of success or expected ratio,
q is the probability of failure and or (1-p)
d is the precision.

This web calculator was produced with The direct link to the calculator is:


Sample Size in Statistics (How to Find it): Excel, Cochran’s Formula, General Tips

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