In a chemical process, the parameters of temperature, pressure, proportion of catalyst, and pH value of the mixture influence the acceptability of the batch. The data from 20 observations are shown in Table 3-15.
(a) Construct a multivariable chart. What inferences can you make regarding the desirable values of the process parameters?
(b) Construct a matrix plot and make inferences on desirable process parameter levels.
(c) Construct contour plots of the proportion nonconforming by selecting two of the process parameters at a time and comment.