In an experiment investigating the hypothesis that aerobic exercise improves concentration and memory, all the participants had an equal chance of being assigned to any of the three conditions in the study. The researchers have used to minimize the possibility of bias when assigning participants to the different groups.

Random assignment

Explanation: Random assignment is an experimental technique used for eliminating placement or assignment bias in a research study. By applying random assignment technique in the scenario given, it gives all the participants an equal chance or opportunity to be placed in any of the three groups or condition in the study. Random assignment eliminates the possible placement bias which might influence the experiment if the participant were manually assigned to the different groups.

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