3. A tire manufacturer has been concerned about the number of defective tires found recently. In order to evaluate the true magnitude of the problem, a production manager selected 10 random samples of 20 units each for inspection. The number of defective tires found in each sample are as follows: Construct a p-chart using three-sigma control limits and assess whether the process is in statistical control. (Hint: If LCL value is calculated to be negative, adjust it to zero since the proportion cannot be negative.) 4. (a) Describe lean systems. What is the defining objective of lean