Patent Document ID: 20110054839
Application ID: 12550981
Patent Flag: 0

Claim One:
1. A method for determining whether the number of samples taken from a population of units where the distribution of X and Y variables are unknown by evaluating ratio mean measurements on a computer to determine a confidence interval comprising: obtaining a sample from a population having two variables X and Y; redefining the multivariate data that comprises the two variables X and Y; using a bootstrapping method, generating a number B of boot strap samples (BSS), where B is a number greater than 100; generating a standardized {circumflex over (Z)} distribution for the ratio mean MR from the B bootstrap samples using the equation Z ^ ( i ) = MR ^ ( i ) - MR ^ SE ^ ( i ) where MR ^ ( i ) is an estimate of the mean for the i th BSS ; where i can range from 1 to B; SE(i) is the standard error for the i th boot strapped sample and wherein standard error is determined by the equation SE ^ ( i ) = ∑ j = 1 n [ AdjMR j ( i ) - MR ^ ( i ) ] 2 n 2 and MR(i) is the ratio mean of the i th bootstrap AdjMR j(i) is the ratio mean for the j th unit for the i th bootstrap; where j is in the range of 1 to n where n is the size of the sample; computing the α th and the (1−α) th percentile of the {circumflex over (Z)} distribution by selecting the value that falls below α% and (1−α) of the data; computing the lower and upper bounds of the confidence interval CI using the equations 
 Lower CI bound={circumflex over (M)}{circumflex over (R)}−ŜÊ* {circumflex over (t)} 1-α Upper CI bound={circumflex over (M)}{circumflex over (R)}−ŜÊ* {circumflex over (t)} α .