Prepare X and R-charts using these data

Analyze the charts and comment on whether the process appears to be in control and stable method described in the chapter

Plastic keychains are being produced in a company keychains produced. The aim is to achieve statistical connamed Hot Shot Plastics. The plastic material is first trol of the curctimes using X and R-charts. molded and then trimmed to the required shape. The Curetime data of 25 samples, each of size four, have curetimes (which is the time for the plastic to cool) dur- been taken when the process is assumed to be in control. ing the molding process affect the edge quality of the 'These are shown as follows. (Nore' The spreadsheet "13 Statistical Process Control" has these data.)