Here we look at a simple example to discover the commonalties of various data analysis techniques widely used in industry today. Careful consideration of the following may result in insights that were not part of your introductory class in statistics.

Our example uses the gate oxide thicknesses for silicon wafers. Two gate oxide tubes are used to diffuse an oxide layer onto silicon wafers. As each batch comes off each of these two production lines, a single wafer from the same location within each batch is selected, and the gate oxide thicknesses are obtained for specific locations on that wafer. The thicknesses in figure 1 are the thicknesses obtained for location number one on each of the wafers selected from 10 successive batches from each line. The target value for this gate oxide thickness is 8490 Angstroms. The specifications are 8475 to 8505 Angstroms. The values are recorded to the nearest Angstrom.

Figure 1: Gate oxide thicknesses in angstroms for 10 wafers from each line

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