Answer
The types of samples are not comparable
Step-by-step explanation
Across cultural study is a specialization in anthropology that uses data that is collected in the field from many societies which is done for the purposes of examining the scope of human behavior and the test hypotheses about human behavior and mental processes which include both their variability and invariance that is under cultural conditions. So in this case where cross-cultural study compared all 300 residents of a remote African village to 300 volunteers from Chicago. The types of samples are not comparable this is because comparative was between different fraternities .