import { zScore } from "https://deno.land/x/simplestatistics@v7.8.3/index.js";
The Z-Score, or Standard Score.
The standard score is the number of standard deviations an observation or datum is above or below the mean. Thus, a positive standard score represents a datum above the mean, while a negative standard score represents a datum below the mean. It is a dimensionless quantity obtained by subtracting the population mean from an individual raw score and then dividing the difference by the population standard deviation.
The z-score is only defined if one knows the population parameters; if one only has a sample set, then the analogous computation with sample mean and sample standard deviation yields the Student's t-statistic.
Examples
zScore(78, 80, 5); // => -0.4
zScore(78, 80, 5); // => -0.4