Fix It on His Experimental Psychology Final Exam, Aaron Is Asked to Asked

Fix It
On his Experimental Psychology final exam, Aaron is asked to describe the similarities and differences between experiments and nonexperiments. His answer is as follows: First, experiments are the best research method. Second, experiments have independent variables, things that the researcher manipulates such as temperature of the room, or difficulty of task. In nonexperimental designs there are no independent variables because researchers do not directly manipulate anything. Validity differs between experiments and nonexperiments. Whereas experiments have less internal validity than nonexperiments, nonexperiments usually have less external validity than experiments. Statistical methods are different for both methods. t-tests and ANOVAs can be used to analyzed experiments, whereas Pearson's r is used to analyze nonexperiments. Sampling also differs between the two methods. Experiments always use random sampling methods and nonexperiments use nonrandom sampling methods. Also, in experiments participants are masked to the purpose of the study, but are not in nonexperiments. In both methods it is important to have a large sample size, when possible, to increase power. Both types of research usually require IRB approval.
Identify and discuss two things that are inaccurate in Aaron's essay, as well as two things that are accurate.