Dr. fletcher decides to give the same measure to another group of 55 participants who decided to not join a fraternity/sorority. doing this would dr. fletcher address all of the following threats to internal validity except:

Experimenter bias

Maturation

Selection

History

Explanation:

Experimenter bias  occurs when the researcher subconsciously affects the result of an experiment such that it delivers a given conclusion. It is one of the biases that are more difficult to prevent.

While carrying out an experiment, the researcher can start to lean towards an idea or a conclusion and start interpreting results to favor this idea. Double Blind techniques can be used to prevent this bias, this a process where the experimenter does not know who an experiment favors.