mekso; binary operator: z-score for the X1 quantile; X2 (default: 1) acts as the descriptor toggle (see notes).
If X2 = 0, then X1 is to be interpreted as a quantile and the output is the corresponding (canonical-gaussian) z-score; if X2 = 1 (which is the default), then X1 is to be interpreted as the area below the canonical gaussian and between the output number of standard deviations from the mean of the canonical gaussian. Thus, zu'oi(X1, 1) = zu'oi((1/2) + (X1 / 2), 0). Example: zu'oi(.95, 1) = zu'oi(.975, 0) = 1.959964...; for more information on this example, see: https://en.wikipedia.org/wiki/1.96 . For the purposes of this definition, the canonical guassian is such that its mean is 0 and its standard deviation is 1. This number is used in confidence interval calculations, via the sample mean and standard error.