Altoona Tire Company sells its ATC-50 tires with a 50,000-mile tread-life warranty. Lorrie Ackerman, a quality control engineer with the company, runs simulated road tests to monitor the life of the output from the ATC-50 production process. From each of the last 12 batches of 1,000 tires, she has tested 5 tires and recorded the following results, with x and R measured in thousands of miles:
Batch 1 2 3 4 5 6 7 8 9 10 11 12 x 50.5 49.7 50.0 50.7 50.7 50.6 49.8 51.1 50.2 50.4 50.6 50.7 R 1.1 1.6 1.8 0.1 0.9 2.1 0.3 0.8 2.3 1.3 2.0 2.1 (a) Use the data above to help Lorrie construct an x chart. (b) Is the production process in-control? Explain.Contact us for the solution