$($a$)$ A production manager is concerned about the low output levels of his employees. The articles that he has read on job performance frequently mention four variables as being important to job performance: $(1)$ skills required for the job, $(2)$ rewards, $(3)$ motivation, and $(4)$ satisfaction.

From the case above:

$1.$Identify the problem.

$2.$ Develop a diagram representing the conceptual model.

$3.$ Develop the hypotheses.

Please give the reference