The customer service department is conducting a survey of the satisfaction level of those who call in for assistance. At the end of the call, customers are asked to rate the service on a 5 point scale, with 5 being the highest level of satisfaction. Anything less than a 5 is considered “defective” by the department. The company receives hundreds of calls per day.
The company has sampled seventy-five calls per day for the last eight days. The number defective in each sample is given in the table below. Calculate the UCL for a 3-standard deviation p-chart of the proportion defective.
Enter your answer below.