A researcher designs an experiment to test memory. He will test three groups of participants. Group 1 will listen to a list of words. Group 2 will read a list of words printed on paper. Lastly, Group...

A researcher designs an experiment to test memory. He will test three groups of participants. Group 1 will listen to a list of words. Group 2 will read a list of words printed on paper. Lastly, Group 3 will hear and read the words. The researcher then tests the participants' memories to see how many words the members of each group can recall. To reduce experimenter and participant bias, what procedure must be used when choosing groups?

 Deception

 Naturalistic observation

 Random assignment

Random sampling

or Research accountability