According to Peterson (2001), which of the following statements is true when using students as research participants? They, as a group, have formed stable political attitudes. They have a well-established sense of self-identity. They are less in need of approval than nonvolunteers. They, as a group, are more homogeneous than nonstudent samples.

As a group they are more homogeneous than nonstudent samples.

Explanation:

A research participant is defined as a person who volunteers in any human subject study or research program after they gave an informed consent to be the subject of the study or the research.

They are also sometime called as the human subject or a human trial.

Now according to Peterson, when students volunteer to participate in  any research study as a human subject, they as a group behave more homogeneous than the other non students samples or non student human subjects.