Miriam has been studying the effects that different genres of music have on an individual's demeanor for 5 years now. according to her research, classical music seems to not elicit any type of aggressive behavior. as she conducts her screen, she makes sure that there are no individuals who like classical music in her group. this is an example of:

Experimenter bias

Explanation:

 The experimental bias is the term which refers to the experimental science phenomena where the final outcome of the experiment are biased towards the expected result.

It is also refers as research bias and due to the subjective influence the researcher affects the data and also the  result. The final results of the experiment are based towards the expect outcome in terms of human experimenter.  

According to the given question, Miriam is studying the various types of effects about the basic genres of the music and in her group she makes sure that the people are not liking the classical music.

 Therefore, Experimenter bias is the correct answer.