Negative binomial is to model the data when dependent variable is count ( integer ) . However, your dependent variable is continuous, so I don't think it is a good idea to use NB. It doesn't matter how many independent variables you have. It is the continuous dependent variable screw things up.

这里有 Hilbe's Negative Binomial Regression 2ed
https://bbs.pinggu.org/thread-1597005-1-1.html