MODIFICATION OF BARTLETT'S STATISTIC
Hui Fu · Jixie qiangdu · 2007
Bartlett's statistic is widely used in test for homogeneity of variances.It is well known that Bartlett's statistic is an approximate χ2 distribution.However,Bartlett's statistic departs far from its χ2 distribution and results in low test precision in small sample situation.Based on mean equality of both Bartlett's statistic and its χ2 distribution,a new modified formulation of Bartlett's statistic is proposed.It can not only be well distributed as χ2 distribution in both large and small sample situation,but also effectively increase test precision.Comparison between modified and traditional Bartlett's statistic is also presented.Furthermore,test methods for simulation results are established,including standard deviation ratio test for two normal populations,mean ratio test for two exponent populations,and two-step simulation method of standard deviation ratio test for multiple populations.