Use the data shown to set up a standardised $\stackrel{}{x}$ and $R$ chart that plots products A and $B.$

on the same control chart. It is assumed that the standard deviation is different for each

product type.

i$)$ Is there different control chart, other than the standardised control chart, that one

could use if the standard deviation of both products was the same? Briefly

explain.

ii$)$ Setup and plot a standardised $\stackrel{}{x}$ and $R$ chart for this process.

iii$)$ Is the process in statistical control? Explain your answer.