Indra wants to investigate the relationship between job status (whether or not they have a job) and grades among college students. She goes to the student center and hands out a survey with two questions about job status and GPA. She finds that at her institution, students with jobs have higher grades than students without jobs. Which of the three causal criteria are established in Indra's study? Established covariance Press Space to open temporal precedence Press Space to open internal validity Press Space to open Not Established