The manager of the Burning Desire candle store wants to understand the purchasing behaviors of her customers. Specifically, she wants to know how many customers who come to the store actually end up making a purchase. In addition, she wants to know what the average purchase price is when customers do make a purchase. She observes customers in the store for a random assortment of times over the course of 5 days, making a total of 20 hours of observation (i. e., 4 hours per day). During each of these hours of observation she counts the number of people who come into the store and notes whether or not they make a purchase. If they do make a purchase, she records the amount they spend. In all, she observes 440 people.