You should use whatever units your model is in everywhere. The distributions are unitless. If you use a normal distribution with a mean of 1, then it will return a sample from a normal distribution with a mean of 1. If your model is in hours and you use this for your process time, then the process will take about an hour.
You can use conversion commands, such as minutes(), to convert from a certain unit of measure to model units. For example:
minutes(normal(1, 0.5))
If your model is in hours, that will return values around 0.0167.
Type a product name
