On a negative note, you discovered that PHP has no native access to sampling distributions, which is a requirement for implementing most statistical tests.
不利的一面，您发现 PHP 对于取样分布缺乏内在手段，而这是实现大多数统计测试所必需的。
The included file, Distribution.php, contains methods that generate sampling-distribution statistics for several commonly used sampling distributions (Student t, Fisher f, Chi Square).
所包含的文件Distribution . php包含了为几个常用的抽样分布(t分布、f分布和X平方分布)生成抽样分布统计信息的方法。
Sampling distributions of mean direction and resultant length were used to develop control charts respectively reflecting the central tendencies and positions of the Angle process.
基于平均方向和合向量长度的抽样分布，研究反映角度过程集中程度的合向量长度控制图和反映角度过程集中位置的平均方向控制图。
应用推荐