各位师兄师姐，小弟在用stata进行零膨胀负二项回归时，输入指令zip crash_freq grade_g logvmt visibility temperature precipitation speed,inf(_cons) vuong nolog后，软件反馈Vuong test is not appropriate for testing zero-inflation.  Specify option forcevuong toperform the test anyway.r(498);
这个应该怎么解决呀，