我用statat软件照着手册，产生10000随机数，然后对其绘图，但是总说我出现错误，不知哪位能帮忙解答
. set obs 100000
obs was 0, now 100000

. set seed 200

. gen x1=invnorm(uniform())*6+100

. gen x2=invnorm(uniform())*6+100

. gen x2=invnorm(uniform())*6+100

. gen x3=invnorm(uniform())*6+100

. gen x4=invnorm(uniform())*6+100

. gen mean=(x1+x2+x3+x4)/4

. sum mean

    Variable |       Obs        Mean    Std. Dev.       Min        Max
-------------+--------------------------------------------------------
        mean |    100000    99.98013    2.992812   87.92355   113.4915

. graph mean,bin(50) xlabel ylabel norm
meangraph_g.new ,bin(50) xlabel ylabel norm: class member function not found
r(4023);