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statistic.ts
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35 lines (31 loc) · 1.1 KB
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import {Math} from 'angular2/src/facade/math';
export class Statistic {
static calculateCoefficientOfVariation(sample, mean) {
return Statistic.calculateStandardDeviation(sample, mean) / mean * 100;
}
static calculateMean(samples: number[]) {
var total = 0;
// TODO: use reduce
samples.forEach(x => total += x);
return total / samples.length;
}
static calculateStandardDeviation(samples: number[], mean) {
var deviation = 0;
// TODO: use reduce
samples.forEach(x => deviation += Math.pow(x - mean, 2));
deviation = deviation / (samples.length);
deviation = Math.sqrt(deviation);
return deviation;
}
static calculateRegressionSlope(xValues: number[], xMean: number, yValues: number[],
yMean: number) {
// See http://en.wikipedia.org/wiki/Simple_linear_regression
var dividendSum = 0;
var divisorSum = 0;
for (var i = 0; i < xValues.length; i++) {
dividendSum += (xValues[i] - xMean) * (yValues[i] - yMean);
divisorSum += Math.pow(xValues[i] - xMean, 2);
}
return dividendSum / divisorSum;
}
}