在使用minitab确定一组数据的分布时，在用最大似然法求参数的时候，发生以下错误，
* WARNING * Newton-Raphson algorithm has not converged after 50 iterations.
* WARNING * Convergence has not been reached for the log-likelihood criterion.
* WARNING * Convergence has not been reached for the parameter estimates  criterion.

现在想调整一下Newton-Raphson的迭代次数，使得程序收敛。请问该如何做。谢谢。