Data Examination

Here the internal consistency of the data as a whole is assessed, again with the intention of assuring the quality of the data for subsequent analysis. The data is examined for patterns and unexpected features.

With so many variates recorded, there are many possible plots that might be displayed which show interesting patterns in the data. Besides the trend and cluster identified in Figure 10, a cursory

  

Figure 11: Three clusters in three dimensional space.

examination reveals many more. For example, the three dimensional scatterplot of day, temperature and jittered speed can be rotated into the position shown in Figure 11 revealing three distinct clusters.

Once patterns have been identified, three decisions are possible: Ignore them, redo the Plan and Data stages, or most likely pass the information on to be handled in the Analysis stage.

Michelson did not question the internal consistency of his data in the paper.