Androx Chemicals manufactures a powdered compound that is used to coat gunite swimming pools. An important measure is the Dry Brightness (DB) Number, and customers will not accept product that has a DB number less than 90.3. Because it is difficult to obtain a precise reading, a technician takes a grab sample of material, divides it into three parts, and then measures each part. The three measurements are then averaged and plotted on control charts. The following data represent 20 samples that were obtained from this process.

a. Use control charts to analyze this process. Is the process in control?
b. Does it appear that the process is meeting the minimum specification limit?
c. What would you recommend as the next step?

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Sample No Sample No Dry Brightness Reading Dry Brightness Reading 91.40 91.10 91.80 91.50 91.70 91.50 91.60 91.70 91.90 91.90 91.90 91.90 91.40 91.30 91.50 91.70 91.50 91.60 91.70 91.90 91.90 91.90 91.80 91.20 91.30 91.50 91.70 91.50 91.60 91.70 91.90 91.90 91.10 91.10 91.80 91.70 91.80 91.40 91.10 91.80 90.50 2 12 13 4 91.1091.70 15 16 17 18 19 20 91.60 92.30 92.00 91.60 91.20 91.30 91.10 91.60 92.0092.30 91.10 91.60 92.30 10