$1.$ A lab process has an average turnaround time of $25\mathrm{.}8$ minutes and a standard deviation of $1\mathrm{.}24$ minutes. The nominal $($target$)$ value for the process is $25$ minutes with an upper specification limit of $30$ minutes and a lower specification limit of $20$ minutes. The lab director wants to have four$-$sigma performance for the lab.

$2$a$.$ For the lab process, the process capability ratio $($Cp$)=?$

$2$b$.$ For the lab process, the process capability index $($Cpk$)=?$

$2$c$.$ Based on the value of Cpk$,$ the lab process meets the four sigma standard. This statement is $\_\_\_\_?$ A$)$ cannot tell whether it is true or false; more information is needed? B$)$ True, C$)$ False