swilk can be used with 7<=n<=2000 observations
sktest requires a minimum of 8 observations to make its calculations.

stata10中绘图命令  help graph

sfrancia can be used with with 5<=n<=5000 observations

. sfrancia x if g==1

                  Shapiro-Francia W' test for normal data
    Variable |    Obs        W'         V'         z     Prob>z
-------------+-------------------------------------------------
           x |      9    1.00000      0.000     -9.970  1.00000

. swilk x if g==1

                   Shapiro-Wilk W test for normal data
    Variable |    Obs        W          V          z     Prob>z
-------------+-------------------------------------------------
           x |      9    0.93477      0.958     -0.070  0.52801

. sktest x if g==1

                   Skewness/Kurtosis tests for Normality
                                                 ------- joint ------
    Variable |  Pr(Skewness)   Pr(Kurtosis)  adj chi2(2)    Prob>chi2
-------------+-------------------------------------------------------
           x |      0.225         0.123            4.13       0.1269
楼上的战友，我继续求助，我用不同的命令检验了一个ob为8的数组，为什么会出现这样的情况。