Applied Engineering Statistics Exam

IE5002 Homework 3

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1. In “Orthogonal Design for Process Optimization and Its Application to Plasma Etching” (Solid State Technology, May 1987), G. Z. Yin and D. W. Jillie describe an experiment to determine the effect of C2F6 flow rate on the uniformity of the etch on a silicon wafer used in integrated circuit manufacturing. Three flow rates are used in the experiment, and the resulting uniformity (in percent) for six replicates is shown here. (𝛼 = 0.05)

(a) Does C2F6 flow rate affect etch uniformity? Construct box plots to compare the factor levels and perform the analysis of variance. What is the approximate P-value? What are your conclusions? (b) Which gas flow rates produce different mean etch uniformities? 2. An experiment was run to determine whether four specific firing temperatures

affect the density of a certain type of brick. The experiment led to the following data. (𝛼 = 0.05) (a) Does the firing temperature affect the density of the bricks? (b) Find the P-value for the F-statistic computed in part (a)

3. An electronics engineer is interested in the effect on tube conductivity of five

different types of coating for cathode ray tubes in a telecommunications system display device. The following conductivity data are obtained. If 𝛼 = 0.05, can you isolate any differences in mean conductivity due to the coating type?

IE5002 Homework 3

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4. An ANOVA output is shown below. Fill in the blanks. You may give bounds on

the P-value.