程序是这样的（按照陈强那本高级计量经济学及stata应用第二版做的，不知道为什么不对）
program onesample, rclass
drop _all
set obs 30
gen x = runiform()
sum x
return scalar mean_sample = r(mean)
end
simulate xbar = r(mean_sample), seed(101) reps(10000): one sample
(在这一行报错了
invalid syntax
an error occurred when simulate executed isample
r(198);


最后一步应该是
hist xbar, normal xtitle("xbar from many sample")

尝试了很多次，以为是命令库没更新，去更新了也不行，，，球球大佬们不吝赐教orzzzzzzz