42 lines
1.3 KiB
TypeScript
42 lines
1.3 KiB
TypeScript
/**
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* @license
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* Copyright Google Inc. All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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export class Statistic {
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static calculateCoefficientOfVariation(sample: number[], mean: number) {
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return Statistic.calculateStandardDeviation(sample, mean) / mean * 100;
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}
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static calculateMean(samples: number[]) {
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let total = 0;
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// TODO: use reduce
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samples.forEach(x => total += x);
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return total / samples.length;
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}
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static calculateStandardDeviation(samples: number[], mean: number) {
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let deviation = 0;
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// TODO: use reduce
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samples.forEach(x => deviation += Math.pow(x - mean, 2));
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deviation = deviation / (samples.length);
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deviation = Math.sqrt(deviation);
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return deviation;
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}
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static calculateRegressionSlope(
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xValues: number[], xMean: number, yValues: number[], yMean: number) {
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// See http://en.wikipedia.org/wiki/Simple_linear_regression
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let dividendSum = 0;
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let divisorSum = 0;
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for (let i = 0; i < xValues.length; i++) {
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dividendSum += (xValues[i] - xMean) * (yValues[i] - yMean);
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divisorSum += Math.pow(xValues[i] - xMean, 2);
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}
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return dividendSum / divisorSum;
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}
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}
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