Explain the reason why random sampling is preferred in psychological studies.

Because it decreases the likelihood of the results to be biased and adds weight to the results reliability

I'm not sure but it could be c ( not a 100% sure )

Iwould suggest the myers-briggs type indicator because the railroad unions are looking for which are focused introverts. the mbti was designed to provide a lot of information about what a person likes and what their personality based on the four-dimension scale. also for an employer it has been extremely to predict how an employee would act in a professional setting. this is what the railroad unions are looking for. they want the railroad workers to be focused and skillful to ensure the safety of everyone around them. but the other assessments don't match the criteria for the unions. like the measure disorder, emotions and self-esteem while the rorschach and tat tests are both projective tests that mainly measure someone’s personality. also, because this job is not easy, it is vital to make sure the employers are hiring the right people for the job.