Download Sample Size Determination in Health Studies
This help file is designed to assist you when you have problems with the program’s interface. For examples and descriptions of each estimation or table, please click on the Examples button in the main window.
The math engine used in the estimate section uses numeric methods that do not guarantee an answer for inverse calculations under extreme conditions. (Here, inverse calculations mean finding any parameter other than the sample size. The accuracy of sample sizes are guaranteed if the other parameters are mathematically valid.)
All formulae are expressed in terms of sample size, n (eg. n=zP/d) and the remaining terms are approximated to 1E-15 where possible, using linear interpolation. Interpolation is the general solution applied to all formulae because it was found that most of the formulae end up being too complicated to be inversed algebraically.
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