**若pro是数值型
g m=.
levelsof pro,l(p)
foreach i in `p'{
sum x if pro!=`i'
replace m=r(mean) if pro==`i'
}
**若pro是字符型
g m=.
levelsof pro,l(p)
foreach i in `p'{
sum x if pro!="`i'"
replace m=r(mean) if pro=="`i'"
}
**若pro是数值型
g m=.
levelsof pro,l(p)
foreach i in `p'{
sum x if pro!=`i'
replace m=r(mean) if pro==`i'
}
**若pro是字符型
g m=.
levelsof pro,l(p)
foreach i in `p'{
sum x if pro!="`i'"
replace m=r(mean) if pro=="`i'"
}