Which of the following elements would help you decide when a cause-and-effect conclusion about the relationship between two variables in an experiment has been reached?
A. a small sample size
B. random selection of participants
C. an international study
D. low-cost study design
B. random selection of participants
Random selection of participants helps to ensure that the sample is representative of the population, increasing the likelihood that any cause-and-effect conclusions drawn from the study can be generalized to the wider population.