An I

$-$

MR chart is established for an in

$-$

control process with X

$-$

bar

$=$

$1$

$9$

$9$

$,$

$$MR

$=$

$3$

$.$

$2$

$,$

$$and span

$=$

$4$

$.$

$$Specifications on

the normally distributed quality characteristic are set at

$2$

$0$

$0$

$\backslash$

pm

$5$

$.$

$$The value of Cpk is therefore estimated as: