13.26 In anthropological studies, an important characteristic of fossils is cranial capacity. Frequently skulls are at least partially decomposed, so it is necessary to use other characteristics to obtain information about capacity.

One such measure that has been used is the length of the lambda-opisthion chord. The article “Vertesszollos and the Presapiens Theory” (American Journal of Physical Anthropology [1971]) reported the accompanying data for n 5 7 Homo erectus fossils.

x (chord length in mm)

78 75 78 81 84 86 87 y (capacity in cm3)

850 775 750 975 915 1015 1030 Suppose that from previous evidence, anthropologists had believed that for each 1-mm increase in chord length, cranial capacity would be expected to increase by 20 cm3. Do these new experimental data strongly contradict prior belief?