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x/simplestatistics/src/standard_normal_table.js

simple statistics for node & browser javascript
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const SQRT_2PI = Math.sqrt(2 * Math.PI);
function cumulativeDistribution(z) { let sum = z, tmp = z;
// 15 iterations are enough for 4-digit precision for (let i = 1; i < 15; i++) { tmp *= (z * z) / (2 * i + 1); sum += tmp; } return ( Math.round((0.5 + (sum / SQRT_2PI) * Math.exp((-z * z) / 2)) * 1e4) / 1e4 );}
/** * A standard normal table, also called the unit normal table or Z table, * is a mathematical table for the values of Φ (phi), which are the values of * the [cumulative distribution function](https://en.wikipedia.org/wiki/Normal_distribution#Cumulative_distribution_function) * of the normal distribution. It is used to find the probability that a * statistic is observed below, above, or between values on the standard * normal distribution, and by extension, any normal distribution. */const standardNormalTable = [];
for (let z = 0; z <= 3.09; z += 0.01) { standardNormalTable.push(cumulativeDistribution(z));}
export default standardNormalTable;