A self-fulfilling prophecy is the social and psychological phenomenon that, when exposed to a personal belief, a person will change its conduct or behaviour in order to confirm or make real that particular belief in order to avoid cognitive dissonance or the fact of being wrong.
Jenna believes she is bad in statistics. But that belief, which is not really or necessarily true, makes her change her behaviour and not study or abandon her effort to become better at statistics, which at the same time makes her perform badly in statistics in the future. This reinforcing loop maintains the belief and prophecy going in time.
According to my research on studies conducted by various psychologists, I can say that based on the information provided within the question this is an example of a Self-fulfilling prophecy. This is defined as a phenomenon of when an individual believes something will happen a certain way, and that event ends up happening only because the individual changed their behaviors and actions causing it to happen. Which is what Jenna did with her statistics class.
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