README.md (6436B)
1 <!-- 2 3 @license Apache-2.0 4 5 Copyright (c) 2018 The Stdlib Authors. 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18 19 --> 20 21 # Poisson 22 23 > Poisson distribution. 24 25 <section class="usage"> 26 27 ## Usage 28 29 ```javascript 30 var poisson = require( '@stdlib/stats/base/dists/poisson' ); 31 ``` 32 33 #### poisson 34 35 Poisson distribution. 36 37 ```javascript 38 var dist = poisson; 39 // returns {...} 40 ``` 41 42 The namespace contains the following distribution functions: 43 44 <!-- <toc pattern="*+(cdf|pmf|mgf|quantile)*"> --> 45 46 <div class="namespace-toc"> 47 48 - <span class="signature">[`cdf( x, lambda )`][@stdlib/stats/base/dists/poisson/cdf]</span><span class="delimiter">: </span><span class="description">Poisson distribution cumulative distribution function.</span> 49 - <span class="signature">[`logpmf( x, lambda )`][@stdlib/stats/base/dists/poisson/logpmf]</span><span class="delimiter">: </span><span class="description">evaluate the natural logarithm of the probability mass function (PMF) for a Poisson distribution.</span> 50 - <span class="signature">[`mgf( t, lambda )`][@stdlib/stats/base/dists/poisson/mgf]</span><span class="delimiter">: </span><span class="description">Poisson distribution moment-generating function (MGF).</span> 51 - <span class="signature">[`pmf( x, lambda )`][@stdlib/stats/base/dists/poisson/pmf]</span><span class="delimiter">: </span><span class="description">Poisson distribution probability mass function (PMF).</span> 52 - <span class="signature">[`quantile( p, lambda )`][@stdlib/stats/base/dists/poisson/quantile]</span><span class="delimiter">: </span><span class="description">Poisson distribution quantile function.</span> 53 54 </div> 55 56 <!-- </toc> --> 57 58 The namespace contains the following functions for calculating distribution properties: 59 60 <!-- <toc pattern="*+(entropy|kurtosis|mean|median|mode|skewness|stdev|variance)*"> --> 61 62 <div class="namespace-toc"> 63 64 - <span class="signature">[`kurtosis( lambda )`][@stdlib/stats/base/dists/poisson/kurtosis]</span><span class="delimiter">: </span><span class="description">Poisson distribution excess kurtosis.</span> 65 - <span class="signature">[`mean( lambda )`][@stdlib/stats/base/dists/poisson/mean]</span><span class="delimiter">: </span><span class="description">Poisson distribution expected value.</span> 66 - <span class="signature">[`median( lambda )`][@stdlib/stats/base/dists/poisson/median]</span><span class="delimiter">: </span><span class="description">Poisson distribution median.</span> 67 - <span class="signature">[`mode( lambda )`][@stdlib/stats/base/dists/poisson/mode]</span><span class="delimiter">: </span><span class="description">Poisson distribution mode.</span> 68 - <span class="signature">[`skewness( lambda )`][@stdlib/stats/base/dists/poisson/skewness]</span><span class="delimiter">: </span><span class="description">Poisson distribution skewness.</span> 69 - <span class="signature">[`stdev( lambda )`][@stdlib/stats/base/dists/poisson/stdev]</span><span class="delimiter">: </span><span class="description">Poisson distribution standard deviation.</span> 70 - <span class="signature">[`variance( lambda )`][@stdlib/stats/base/dists/poisson/variance]</span><span class="delimiter">: </span><span class="description">Poisson distribution variance.</span> 71 72 </div> 73 74 <!-- </toc> --> 75 76 The namespace contains a constructor function for creating a [Poisson][poisson-distribution] distribution object. 77 78 <!-- <toc pattern="*ctor*"> --> 79 80 <div class="namespace-toc"> 81 82 - <span class="signature">[`Poisson( [lambda] )`][@stdlib/stats/base/dists/poisson/ctor]</span><span class="delimiter">: </span><span class="description">Poisson distribution constructor.</span> 83 84 </div> 85 86 <!-- </toc> --> 87 88 ```javascript 89 var Poisson = require( '@stdlib/stats/base/dists/poisson' ).Poisson; 90 91 var dist = new Poisson( 2.0 ); 92 93 var y = dist.pmf( 3.0 ); 94 // returns ~0.18 95 96 y = dist.pmf( 2.3 ); 97 // returns 0.0 98 ``` 99 100 </section> 101 102 <!-- /.usage --> 103 104 <section class="examples"> 105 106 ## Examples 107 108 <!-- TODO: better examples --> 109 110 <!-- eslint no-undef: "error" --> 111 112 ```javascript 113 var objectKeys = require( '@stdlib/utils/keys' ); 114 var poisson = require( '@stdlib/stats/base/dists/poisson' ); 115 116 console.log( objectKeys( poisson ) ); 117 ``` 118 119 </section> 120 121 <!-- /.examples --> 122 123 <section class="links"> 124 125 [poisson-distribution]: https://en.wikipedia.org/wiki/Poisson_distribution 126 127 <!-- <toc-links> --> 128 129 [@stdlib/stats/base/dists/poisson/ctor]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/ctor 130 131 [@stdlib/stats/base/dists/poisson/kurtosis]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/kurtosis 132 133 [@stdlib/stats/base/dists/poisson/mean]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/mean 134 135 [@stdlib/stats/base/dists/poisson/median]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/median 136 137 [@stdlib/stats/base/dists/poisson/mode]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/mode 138 139 [@stdlib/stats/base/dists/poisson/skewness]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/skewness 140 141 [@stdlib/stats/base/dists/poisson/stdev]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/stdev 142 143 [@stdlib/stats/base/dists/poisson/variance]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/variance 144 145 [@stdlib/stats/base/dists/poisson/cdf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/cdf 146 147 [@stdlib/stats/base/dists/poisson/logpmf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/logpmf 148 149 [@stdlib/stats/base/dists/poisson/mgf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/mgf 150 151 [@stdlib/stats/base/dists/poisson/pmf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/pmf 152 153 [@stdlib/stats/base/dists/poisson/quantile]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/poisson/quantile 154 155 <!-- </toc-links> --> 156 157 </section> 158 159 <!-- /.links -->