Assume you are working in a plant as a chemical engineer. One of your tasks ...

     Assume you are   working in a plant as a chemical engineer. One of your tasks is to monitor pH   of a specific process. Each day, you record the pH of the process at three   different time of the day. The data for the past few days is presented in the   following table. we know that standard deviation of the pH of the process is   0.1. Based on the collected data, construct two control charts that monitor   the average and variability of the pH of the process. Is the average and   variability of the process in control?   Day   Monday   Tuesday   Wednesday   Thursday   Calculate the center line to control the   average of pH of the process.   Calculate the average of ranges to   control the variability of pH of the process.   Number of observation in each sample (n):   a. D4   b. D3   Upper Control Limit to control average of   the pH of the process:   Lower Control Limit to control average of   the pH of the process:   Is the average of the pH of the process   in control?        a. Yes   b. No   Upper Control Limit to control   variability of the pH of the process:   Lower Control Limit to control   variability of the pH of the process:   Is the variability of the pH of the   process in control?   a. Yes   b. No