就这个数据,前面的是个平均值,各有4-6份样品,拿35个均值做正态性检验,就得出我提问之前那个图,统计量为0.923
不好意思,我之前没看清,你的0.923就是Shapiro-Wilks test的统计量,SPSS称它为Shapiro-Wilk‘s W值,其对应的P值就是依据0.923计算出来的。我查了SPSS帮助系统,没有说Shapiro-Wilk‘s W值服从正态分布(其他权威文献也没有说Shapiro-Wilk‘s W值服从正态分布),SPSS通过线性插值法在其模拟的临界值范围内求出其P值(原文:Based on the computed W statistic, the significance is calculated by linearly interpolating within the range of simulated critical values given in Shapiro and Wilk (1965).)另一篇文献这样解释:W may be thought of as the squared correlation coefficient between the ordered sample values (X') and the wi. The wi are approximately proportional to the normal scores Mi. W is a measure of the straightness of the normal probability plot, and small values indicate departures from normality.大致意思:W值是有序样本(将样本值从小到大排列,并计算其比例值)与对应的正态分布比例值的相关系数的平方值,也就是对P-P图的直线程度测量(若数据在P-P图呈对角直线分布就符合正态分布),小的W值就表明背离正态分布。