This research was carried out using a method referred as ‘stratified sampling’. The total population was divided into homogeneous, non-overlapping sub-population groups, called ‘strata’. This stratified sampling method is indi- cated for similar research, because it presents smaller losses in the evaluation of the various parameters com- pared with the ‘simple random sampling’ method [40]. People were divided into four strata on the basis of their specialty in the hospital. The strata were as follows: stra- tum Α: doctors; stratum Β: nurses; stratum C: adminis- trative Staff; stratum D: medical students.