Suppose that a manufacturer of a particular automotive part classifies each unit produced as either defective or non defective. Each hour 200 parts are randomly selected from a very large batch of manufactured items and tested for possible defectiveness. The file P20_20.xlsx lists the number of defective parts (out of the 200 sampled) found during each of 30 consecutive hours of production.

a. Based on the given sample data, is this production process currently in control? Provide support for your conclusions.

b. What advice, if any, would you give to the managers of this production process?