Professor Bingham measures the cognitive skills of one hundred 30-year-olds and compares them with one hundred 50-year-olds.This is an example of which method?

A) Cross-sectional
B) Longitudinal
C) Sequential
D) Clinical

This is an example of a cross-sectional study because the researcher is comparing cognitive skills between two different age groups at the same time. A longitudinal study would involve measuring the cognitive skills of the same individuals over a period of time, while a sequential study would involve combining elements of both cross-sectional and longitudinal studies to examine the effects of both age and time on cognitive skills. A clinical study would involve examining a specific condition or disease in a controlled environment.