There is a good argument supporting the idea that a winning mindset significantly helps deliver winning results. We're not talking Stuart Smalley stuff, but research-backed, elite-tested mental strategies. Assuming that the boys end the semester having a solid grasp of what has happened over the previous two quarters, there is every reason to expect strong results on exams. Conversely, if they have set their engine throttle to the cruise-control governor, then these exams may be unnecessarily arduous.
All too often, Lower School students get exposed for displaying poor stamina in the face of semester exams. Sustaining an effort over a period of time, in this case two quarters and an exam, is an essential discipline of both a good student and a good person. Hard work, resilience, grit...Therefore, we want to see these boys exhibit and experience sustained effort as much as we want to see them score well on exams.
Therefore, parents can help practically by guiding their sons through some of the exercises mentioned in the linked article above. Areas like: seeing success, staying positive, mindfulness and presence, pushing through, not panicing, projecting confidence, managing discomfort, honestly evaluating their progress, and developing selective amnesia (long-term memory for success and a short-term memory for failure); all are discussed by Dr. Afremow.