Question $1$

$($a$)$ What is Statistical Process Control $($SPC$)?$ Explain the purpose of using SPC in

quality engineering and how it differs from other quality control methods.

$(8$ marks$)$

$($b$)$ Explain the difference between common cause variation and special cause

variation and provide examples of each. How can SPC be used to distinguish

between these types of variation?

$(10$ marks$)$

$($c$)$ Develop a process capability analysis to compare two different manufacturing

processes using the dataset provided in table $1.$ The part being manufactured has

a specification of $25\mathrm{.}5+-0\mathrm{.}5mm.$

Fifteen readings of three samples each were taken for each process. The data in

table $1$ shows the mean and range of the samples measured. Analyse the data

and choose which process you think would be ideal for the product specification,

giving reasons for your choice.

$(15$ marks$)$