CI95 ( AllData )
CONFIDENCE INTERVAL CALCULATION (95%) = IC95
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Paolo Marchetto - Show more from this author
Function definition: (Copy & paste into FileMaker's Edit Custom Function window)
CONFIDENCE INTERVAL CALCULATION (95%) = CI95
CI95 (of an mean) = Mean( AllData ) +/- t * STDerr
STDerr is the standard error;
The standard error of a mean is obtained by dividing the standard deviation by the square root of the sample's (AllData) numerosity (n).
AllData is the content of a multiple field or the content of a field read via a one-to-many relationship.
t is a coefficient derived from the "Table of t-values for Student's distribution" (here it's predetermined from a simplified table). You must take into account that the degrees of freedom in Italian 'Gradi Di Libertà' (GDL) are calculated as follow: AllData size - 1.
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