At first, all the investigations that are performed in the case study department were broadly classified into the categories as given in Table 2 It is to be noted that there may be other types of investiga- tions apart from the ones mentioned in Table 2. The investigations listed here are the ones that the sample of patients had undergone over the time period of data collection. In the list given in Table 2, some investigations have been sub-classified (the MRI brain scans have been classified into three categories, viz., Brain 1, Brain2 and Brain3; angiogram investigations into two categories, viz., MR An- giogram and MR Angiogram and screening investigations into two categories, viz., Screening and Screening2). These are the in vestigations having high service time variability. This classification has been made on the assumption that on seeing some characteris tics of the patient and the directions given by the physician about the number of locations of the body part to be investigated, the