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Calculates statistical cumulative distribution function from data array of x values.
npm i cumulative-distribution-function -S
None. Suitable for usage on nodejs or on the browser, via browserify.
const cdf = require('cumulative-distribution-function');
Pass a numeric data array as input,
cdf(data) returns a function, the empirical cumulative distribution function,
a step function that counts the proportion of data less than or equal to the input x.
The function returned by cdf(data) takes a number x and returns the proportion of values less than or equal to x.
var mydata = [13,2,5,3,23,7,11,13,19,23]; var mycdf = cdf(mydata); // cdf(mydata) returns a **function**, so mycdf is a **function** mycdf(-5) // 0.0 because all mydata are greater than -5 mycdf(2) // 0.1 because 1 of 10 mydata are less than or equal to 2 mycdf(3) // 0.2 because 2 of 10 mydata are less than or equal to 3 mycdf(13) // 0.7 because 7 of 10 mydata are less than or equal to 13 mycdf(19) // 0.8 because 8 of 10 mydata are less than or equal to 19 mycdf(20) // 0.8 because 8 of 10 mydata are less than or equal to 20 mycdf(25) // 1.0 because all mydata are less than or equal to 25 mycdf.xs() // returns [2, 3, 5, 7, 11, 13, 19, 23] from sorted, unique mydata mycdf.ps() // returns [0.1,0.2,0.3,0.4,0.5,0.7,0.8,1.0] from corresponding cumulative proportions
##Missing or Empty Data
Calling cdf with a missing or empty data array returns a function that returns undefined.
.ps() auxiliary functions will return empty arrays.
var mycdf = cdf(); // empty or missing data mycdf(5) // returns undefined mycdf.xs() // returns empty array  mycdf.ps() // returns empty array 
Use mocha framework.
Copyright 2016 Paul Brewer, Economic and Financial Technology Consulting LLC