Unlike the sensitivity and inverse sensitivity analysis, the Monte-Carlo analysis simulates the effect of all perturbations simultaneously. For each Monte-Carlo cycle, all of the parameters which have specified tolerances are randomly set using the defined range of the parameter and a statistical model of the distribution of that parameter over the specified  range. Also, by default, all parameters are assumed to follow the same normal distribution with a total width of four standard deviations between the extreme minimum and maximum allowed values.

This default model may be changed using the STAT command, however this is outside the scope of this article. For the purposes of this article, configure the Monte-Carlo tab as follows:



The 'Overlay MC graphics' control will automatically update and overlay any open graphic window with the results from the Monte Carlo run. This is extremely useful as a way of establishing whether tolerances are close to giving good results or not.