A professor is interrupted independently by phone calls (at rate 1.3/h), by students with questions (at rate 0.6/h), and by colleagues (at rate 0.3/h). How many interruptions might she expect during an 8-h day? What is the expected time between phone calls, between students, between colleagues, and between interruptions of all kinds?
Find the parameter A for the Poisson distribution that describes the given process.