The rest of the paper is organized as follows. In Section 2 we present the formulation of the problem. At first, we propose the staffing model used for computing the useful data of the scheduling problem. Then we introduce the distributionally robust chance-constrained approach. In Section 3 we propose computations leading to the deterministic equivalent of the distributionally robust program. We also present the piecewise linear approximations leading to the final programs whose solutions are lower and upper bounds of the initial optimal solution. Section 4 gives an illustrative example of our approach. Finally in Section 5 we give numerical results.