You are waiting at the end of a line at a checkout counter. There are 7 customers in front of you and the cashier has just begun serving the first one. The length of time it takes to serve a customer is an exponential random variable with a mean value of 1 minute, and each customer's service time is independent of the others. (a) What kind of random variable is your waiting time in this line? (Hint: the stream of satisfied customers leaving the store is a Poisson process) (b) What is your average waiting time? (c) What is the standard deviation of your waiting time