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x/simplestatistics/src/t_test.js

simple statistics for node & browser javascript
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import mean from "./mean.js";import standardDeviation from "./standard_deviation.js";
/** * This is to compute [a one-sample t-test](https://en.wikipedia.org/wiki/Student%27s_t-test#One-sample_t-test), comparing the mean * of a sample to a known value, x. * * in this case, we're trying to determine whether the * population mean is equal to the value that we know, which is `x` * here. Usually the results here are used to look up a * [p-value](http://en.wikipedia.org/wiki/P-value), which, for * a certain level of significance, will let you determine that the * null hypothesis can or cannot be rejected. * * @param {Array<number>} x sample of one or more numbers * @param {number} expectedValue expected value of the population mean * @returns {number} value * @example * tTest([1, 2, 3, 4, 5, 6], 3.385).toFixed(2); // => '0.16' */function tTest(x, expectedValue) { // The mean of the sample const sampleMean = mean(x);
// The standard deviation of the sample const sd = standardDeviation(x);
// Square root the length of the sample const rootN = Math.sqrt(x.length);
// returning the t value return (sampleMean - expectedValue) / (sd / rootN);}
export default tTest;