which of the four common flaws in research is in operation: sampling bias, distortions in self-reported data, experimenter bias, or placebo effect....

which of the four common flaws in research is in operation: sampling bias, distortions in self-reported data, experimenter bias, or placebo effect. More than one flaw may apply.

Students from a psychology course were asked to serve as experimenters in a study where rats were timed navigating mazes. Students were told that the rats differed genetically. One group was told that their rats were "maze-bright," and the other group was told that their rats were "maze-dull." All of the students were then asked to run an experiment on how well their rats navigated the maze. When the results came back