没有怎么学过统计，不过现在有个任务是用HLM处理统计数据的，结果出现了这种情况，不知道是怎么回事，麻烦各位高手帮忙解答一下，灰常感谢~~~问题如下
There is a problem in the fixed portion of the model.  A near singularity is
likely.  Possible sources are a collinearity or multicollinearity among the
predictors.  We suggest that you examine a correlation matrix among the fixed
effect predictors.