$2$uestion $3$ :

$($a$)$ Statistical Process Control is now a widely used technique for

maintaining quality in volume manufacturing situations. Describe

carefully what is meant by the capability of a process and distinguish

between $C_m,C_{mk},C_p$ and $C_{pk}.$

$($b$)$ The specification for the output voltage on a dry cell after manufacture

is $9\mathrm{.}00+-0\mathrm{.}25V.$ Thirty consecutively manufactured units were tested

prior to carrying out a production run. The mean and standard

deviation are $9\mathrm{.}10$ V and $0\mathrm{.}06$ V $,$ respectively.

Calculate the appropriate capability indices. Do you consider it safe to

proceed with the production run? Justify your decision.