A process is in statistical control with $*=39$ and R $=2\mathrm{.}5.$ The control chart uses a sample size of n $=2.$

Specifications are set at $40+5.$ The quality characteristic is normally distributed. Therefore, the actual process capability $($Cpk$)$ is estimated as Answer

$0\mathrm{.}60$

$0\mathrm{.}71$

$0\mathrm{.}80$

$0\mathrm{.}90$

$0\mathrm{.}81$