Contemporary economics contains mainly two approaches for an explanation of fluctuations of economic activity indicators. The first approach expresses fluctuations as consequences of random external shocks. The second approach expresses fluctuations as a deterministic dynamical process producing more complex behaviour of the economic system. In our article both approaches are applied. A purpose of our paper is to re-formulate traditional Goodwin predator-prey model by including a specific differential equation describing technological progress in deterministic and/or stochastic way. A base of this system contains such variables in interest as a rate of employment, a share of labour, and different forms of a rate of the technological progress.