kurtosis.js (1431B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var isnan = require( '@stdlib/math/base/assert/is-nan' ); 24 25 26 // MAIN // 27 28 /** 29 * Returns the excess kurtosis for a normal distribution with mean `mu` and standard deviation `sigma`. 30 * 31 * @param {number} mu - mean 32 * @param {PositiveNumber} sigma - standard deviation 33 * @returns {number} excess kurtosis 34 * 35 * @example 36 * var y = kurtosis( 0.0, 1.0 ); 37 * // returns 0.0 38 * 39 * @example 40 * var y = kurtosis( 5.0, 3.0 ); 41 * // returns 0.0 42 * 43 * @example 44 * var y = kurtosis( NaN, 1.0 ); 45 * // returns NaN 46 * 47 * @example 48 * var y = kurtosis( 0.0, NaN ); 49 * // returns NaN 50 * 51 * @example 52 * var y = kurtosis( 0.0, 0.0 ); 53 * // returns NaN 54 */ 55 function kurtosis( mu, sigma ) { 56 if ( 57 isnan( mu ) || 58 isnan( sigma ) || 59 sigma <= 0.0 60 ) { 61 return NaN; 62 } 63 return 0.0; 64 } 65 66 67 // EXPORTS // 68 69 module.exports = kurtosis;