means of observation, Research is called observation research, Such as measuring the degree of aggressive behavior after presenting a simple frustrating stimulus, and the means of interrogation, reconnaissance or questionnaire, It comes in the form of an interview, field survey, or in the form of applying psychological tests or graded assessment lists, and the means of intervention, That is, the examiner becomes part of the sample he is studying or a participant in the experiment, When the researcher conducts an experiment, It aims to recognize causal relationships between variables.