Record and make note of the total units output by an entity. For example, if you are examining the quality of a shipment of soup cans, you must make a note of how many total units are in the shipment. This number will be referred to as "x."
Record and make note of the faulty units output. Following the soup example, you must make note of all faulty cans of soup in the shipment. This number will be referred to as "y."
Divide "x" by "y." This number is the p-bar.