7.7 In Example 6.5, a milling process for corn was discussed in terms of yield of grits.

(a) Assume Batch is a random effect and fit an appropriate linear mixed model.

(b) Produce an appropriate set of residual diagnostic plots and comment on whether or not you feel there are any unusual observations.

(c) Produce a normal Q-Q plot for the random Batch effect and comment on whether or not you feel that the assumed distribution for the Batch effect is appropriate.