EXAMPLE 2-8 Hospital Emergency Visits The following table summarizes visits to emergency departments at four hospitals in Arizona. People may leave without being seen by a physician, and those visits are denoted as LWBS. The re- maining visits are serviced at the emergency department, and the visitor may or may not be admitted for a stay in the hospital. Hospital 2 3 4 Total Total 5292 6991 5640 4329 22.252 LWBS 195 270 246 242 953 Admitted 1277 1558 666 984 4485 Not admitted 3820 5163 4728 3103 16.814 Let A denote the event that a visit is to Hospital I and let B denote the event that the result of the visit is LWBS. Calculate the number of outcomes in A n B, A' , and A U B