Auto pistons at Wenming$$ Chung's plant in Shanghai are produced in a forging$$ process, and the diameter is a critical factor that must be controlled. From sample sizes of $10$ pistons produced each$$ day, the mean and the range of this diameter have been as$$ follows:

$$

Day

Mean x

$($mm$)$

Range R

$($mm$)$

$1$

$158\mathrm{.}9$

$4\mathrm{.}4$

$2$

$151\mathrm{.}2$

$4\mathrm{.}6$

$3$

$153\mathrm{.}6$

$3\mathrm{.}9$

$4$

$153\mathrm{.}5$

$5\mathrm{.}0$

$5$

$154\mathrm{.}6$

$4\mathrm{.}3$

Part $2$

$$a$)$ What is the value of x$?$

x$=154\mathrm{.}36154\mathrm{.}36$ mm $($round your response to two decimal$$ places$).$

Part $3$

$$b$)$ What is the value of R$?$

R$=4\mathrm{.}444\mathrm{.}44$ mm $($round your response to two decimal$$ places$).$

Part $4$

$$c$)$ What are the UCLx and LCLx using $3-$sigma$?$

Upper Control Limit $($UCLx$)=155\mathrm{.}73155\mathrm{.}73$ mm $($round your response to two decimal$$ places$).$

Part $5$

Lower Control Limit $($LCLx$)=152\mathrm{.}99152\mathrm{.}99$ mm $($round your response to two decimal$$ places$).$

Part $6$

$$d$)$ What are the UCLR and LCLR using $3-$sigma$?$

Upper Control Limit $($UCLR$)=7\mathrm{.}897\mathrm{.}89$ mm $($round your response to two decimal$$ places$).$

Part $7$

Lower Control Limit $($LCLR$)=$ enter your response here mm $($round your response to two decimal$$ places$).$