Consider the visits that result in leave without being seen (LWBS) at an emergency department in Example 2.6. Assume that people independently arrive for service at hospital l.
a. What is the probability that the fifth visit is the first one to LWBS?
b. What is the probability that either the fifth or sixth visit is the first one to LWBS?
c. What is the probability that the first visit to LWBS is among the first four visits?
d. What is the expected number of visits until the third LWBS occurs?