Discuss the following: a) b) c) The usefulness of models in managerial decision-making within firms. (5 marks) Process of theory formulation/model building (using an example of a theory/model known to you) (10 marks) Ideally a model should be constructed to fully explain and predict a given phenomenon. Discuss with reference to the criteria for testing the validity of a model and the ensuing debate by Milton Friedman and Paul Samuelson. (10 marks)