A barber shop has homogeneous, independent arrivals every 10 minutes. The interarrival times are exponentially distributed. Each customer renders a tip to the barber, the tip size being Binomially distributed with p=.5 and n=10.

• How many customers are expected to arrive in two hours of operations?
• What is the pdf of the number of customers arriving in 2 hours of ops?
• What is the expected value and variance of a tip?Hint: find E[tip^2] using a spreadsheet
• What is the mean and variance of the total tips received in 2 hours of ops?