A study designed to investigate an increase in traffic accidents at five major intersections finds that road signs near all of the intersections were changed during the month before the increase in accidents was observed. Which of the following experimental designs was used to obtain the findings?
A) Ex post facto design
B) Crossover design
C) Longitudinal design
D) Cross-sectional design

Question

Quizplus · Accepted Answer

An ex post facto design is used to investigate the potential causes of an observed effect by examining existing conditions or events that have already occurred, such as the change in road signs before the increase in accidents.

A Study Designed to Investigate an Increase in Traffic Accidents