An economic model is a description of some features of the economic world that includes features assumed necessary to explain the . a. only those; observed b. all the; observed c. all the; unobserved d. only those; unobserved

Francine, a college freshman, has agreed to participate in a psychology research study. before she begins her participation, she reads a statement written by the researcher explaining the purpose of the research and the potential risks of participation. it also explains that francine is free to withdraw from the research at any time. in providing francine with this statement, the researcher has followed the ethical guidelines of for participants.