effective against these type of shifts?
(c) [2 Marks] There are situations where we have variables sample sizes, therefore, the three
approaches to handle such situations when making Shewhart control charts are:
(i)
(ii)
(iii)
(d) [10 Marks] Control charts for $\bar{x}$ and R are maintained for an important quality characteristics.
The sample size is n = 7; $\bar{x}$ and R are computed for each sample. After 35 samples, we found
that $\sum_{i=1}^{35} x_i = 7805$ and $\sum_{i=1}^{35} R_i = 1200$.
(i) [2 Marks] Set up a $\bar{x}$ and R charts using the above given data.
(ii) [2 Marks] Assuming that both charts exhibit control, estimate the process mean and
standard deviation.
(iii) [3 Marks] If the quality characteristics is normally distributed and if the
specifications are 220 \pm 35, Can the process meet the specifications.
(iv) [3 Marks] Estimate the fraction nonconforming.
(e) [4 Marks] Compare the efficiency of monitoring a process mean using Shewhart and
CUSUM charts for smaller and larger shifts in the process mean by giving the reasons.
