请问最优尺度回归能使用二分类自变量吗?为什么我一使用二分类自变量就出现这样的警告:Variable Q1 has zero variance.This may be due to treating missing data an listwise,or to speciifying supplementary,or to weighting objects with zero weights.Only Descriptive tables can be computed。应该怎么解决?谢谢各位啦