不太明白题目的意思，我是菜鸟，题目是考虑一西班牙女性，tuition=950 bytest=58, incomehi=0等等，要求划出dist与ed的图，可是把这些参数输入后，根本就显示不出来图。 twoway (lfit y1 dist if dist >=0& dist <=10& hispanic ==1& female ==1& tuition ==950& bytest ==58& inc> omehi ==0& ownhome ==0 &dadcoll==1& momcoll ==1 &cue80 ==7.1& stwmfg80 ==10.06) (qfit y3 dist if dist > >=0& dist <=10& hispanic ==1& female ==1& tuition ==950& bytest ==58& incomehi ==0& ownhome ==0 &dadco> ll==1& momcoll ==1 &cue80 ==7.1& stwmfg80 ==10.06)(note:  regress could not fit model)要怎么写命令呀？这是怎么一回事呀，是我命令写错了吗？