According to the authors of the text, the goal of process control is:

to identify normal variability to take action to identify its source

identify whether the observed vriability in performance is normal or abnormal

to ensure the process is not tamper proof

to be able to react immediately to all fluctuations in the performance over time

Question $6$

A process manager wants to use control charts to control their process. They have decided that each

sample should have $4$ observations. The number of standard deviations the manager wants to use is $3.$

The manager found that the average range of the samples is $5.$ The grand average of the samples is

$6\mathrm{.}0.$ The standard deviation of the observations is $2.$ The manager took $20$ samples to use to calculate

the control limits$.$ The formulas used to calculate the control limits is:

$UC{L}_x=x_{\frac{?}{\text{b}\text{a}\text{r}}\frac{?}{\text{b}\text{a}\text{r}}}+\frac{zs}{\sqrt[\phantom{2}]{n}}$

In this example, $n=$

$4$

$5$

$6$

$20$