Random values

Simulations are conducted by generating random values from the probability distributions in the model.

A computer program should normally be used to generate random values. The program Excel contains functions that can be used.

Generating categorical and numerical values is usually based on random values that are equally likely to take any value between 0 and 1. Such a value is said to come from a rectangular (or uniform) distribution between 0 and 1 and has the probability density function shown below.

A value can be generated from a rectangular distribution with the Excel function "=RAND()" or, by hand, by generating a sequence of random digits (e.g. by rolling a 10-sided die).