. A 24℃) design has been used to investi-

gate the effect of four factors on the

(a) Estimate the factor effects. Plot the effect estimates on a normal proba-
bility scale.

(b) Identify a tentative model for this process. Fit the model and test for curvature.

(e) Plot the residuals from the model in part

(b) versus the predicted resistiv-
ity. Is there any indication on this plot of model inadequacy?

(d) Construct a normal probability plot of the residuals. Is there any reason to doubt the validity of the normal-
ity assumption?

Transcribed Image Text:

resistivity of a silicon wafer. The data from this experiment are shown here. Rua A B D Resistivity 12 3 4 + 1 ++1 33.2 4.6 31.2 5 6 7 +1 + +1 1 +1 9.6 40.6 162.4 39.4 8 158.6 9 0 0 0 63.4 2=2 10 0 0 0 0 62.6 11 0 0 0 0 58.7 12 0 0 0 0 60.9