Stat > Reliability/Survival > Repairable System Analysis > Parametric Growth Curve > Options
Use starting estimate for shape
If you have starting estimates for the shape of the distribution model, enter one column to apply to all the response variables, or enter a separate column for each response variable. If you provide fewer starting estimates than there are response columns, the last shape value listed is used for the remaining variables.
The maximum likelihood solution may not converge if the starting estimates are not in the neighborhood of the true solution. If the algorithm does not converge to a solution, you can specify what you think are good starting values.
Maximum number of iterations
Enter a positive integer to specify the maximum number of iterations for the maximum likelihood method. The default is 20. Minitab uses the modified Newton-Raphson algorithm, a recursive method, to calculate the maximum likelihood estimates. If Minitab reaches the maximum number of iterations before convergence, the command terminates.