Consider now a system with two inputs, both of which are random (or pseudorandom, in the case of non-deterministic data). For instance, let's consider a system with the following inputs and outputs:

- X: non-deterministic data input
- Y: disruptive noise
- Z: System output

Our system satisfies the following mathematical relationship:

Where *g* is the mathematical relationship between the system input, the disruptive noise, and the system output. By knowing information about the distributions of X and Y, we can determine the distribution of Z.