I want to ask you, the reader, to be a scientist and try to make sense of data that link parents and offspring.  Consider one plot (of your own choosing) from figures 1-4 depicting heights of 63 undergraduate college students and their parents.  (I collected these data in the USA in the mid to late 1990s.)  What patterns can you discern?  What ideas or questions do you have about the causes producing those patterns?  What questions or reservations do you have about the process you go through in answering these questions?

Figure 1. Son’s vs. father’s height (inches)

Figure 2. Daughter’s vs. mother’s height (inches)

Figure 3. Student’s vs. average of parents’ height (inches)

Figure 4. Father’s vs. mother’s height (inches)

 

Discussion continues in the next post.

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Extracted from Taylor, P. “Why was Galton so concerned about ‘regression to the mean’? -A contribution to interpreting and changing science and society” DataCritica, 2(2): 3-22, 2008, http://www.datacritica.info/ojs/index.php/datacritica/article/view/23/29.