34 lines
883 B
JavaScript
34 lines
883 B
JavaScript
const sum = (arr) => arr.reduce((a, b) => a + b, 0);
|
|
|
|
function getStdev(arr) {
|
|
if (Array.isArray(arr) && arr.length > 0) {
|
|
const n = arr.length;
|
|
const mean = arr.reduce((a, b) => a + b) / n;
|
|
return Math.sqrt(
|
|
arr.map((x) => Math.pow(x - mean, 2)).reduce((a, b) => a + b) / n
|
|
);
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
export const avg = (arr) => sum(arr) / arr.length;
|
|
|
|
export const geomMean = (arr) => {
|
|
let n = arr.length;
|
|
let logavg = sum(arr.map((x) => Math.log(x))); // works for low numbers much better, numerically
|
|
let result = Math.exp(logavg / n);
|
|
return result;
|
|
};
|
|
|
|
export const getCoefficientOfVariation = (arr) => {
|
|
let nonPositiveNumbers = arr.filter((x) => x <= 0);
|
|
if (nonPositiveNumbers.length == 0) {
|
|
let gm = geomMean(arr);
|
|
let stdev = getStdev(arr);
|
|
return stdev / gm;
|
|
} else {
|
|
return getStdev(arr) / avg(arr);
|
|
}
|
|
};
|