关于正态分布的等距分组

一组数据进行等距分组,到底分多少组?美国人斯特.杰斯(sturges)给出经验公式:n=1+3.322lgN又有a=R/n=R/1+3.322lgN.这里n-组数,N-单位数a-组距,R-全距,a的确定,经验公式远远不够,只能作参考.为此对正态分布进行研究.得到下列结果:1)一组数据,计算均值μ及方差σ~2,得出似合密度,由a与σ~2关系.得出a的上界公式.2)给出找出a的算法.这个算法,简单实用且用途广泛.

The Isometric Group about Normal and the Skewed Distribution

Because of thinking only the number of data but not fitting function,we would be adequate to take a farther afield when calculating group data with empirical formula. We have proved the three theorems based on studying the normal distribution,and then reach the conclusion there is a better method to do the same work.The method is simpler and more practical than empirical method and also work well with any skewed distribution.