Professor Thomas and his assistants should use Random assignment because the two groups result from the different amount of people to which they are exposed.
In psychology experiments, random assignment relates to the usage of probability processes to guarantee that each participant has the same probability of being allocated to any particular group.
The two groups result from the different amount of people in the room to which the groups are exposed, the researchers would use random assignment.
This method is used in a psychological experiment, as a chance procedure to ensure that every single participant has the same probability of getting assigned in any mentioned group.
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