DISCRETE PROBABILITY DISTRIBUTIONS 183 3. FILE Compute the mean and variance of the following probabill x P(x) 10 3 15 .2 20 4 Which of these va a. The number of new accounts established by a salesperson in a year b. The time between customer arrivals to a bank ATM. c. The number of customers in Big Nick's barber shop. d. The amount of fuel in your car's gas tank. e. The number of minorities on a jury f. The outside temperature today 4. riables are discrete and which are continuous random variables