A once-popular exercise in the late 19th and early 20th centuries involved attempts at ?nding mathematical expressions that will allow one to pre- dict, for a population of humans, some physical human attribute on the basis of a different one. The data in Table 16.4 shows the result of a classic example of such an exercise where the cranial circumference (in cms) and the length of the longest ?nger (in cms) of 16 individuals were determined. Postulate a linear two-parameter model as in Eq (16.19), obtain least-squares estimates of the slope and intercept, and test hy- potheses that these parameters are not signi?cantly different from zero. Plot the data versus the model ?t and comment on the results.