What is the test for reversing a jury's verdict in a personal injury case?

Unquestionably, the evidence on this question is circumstantial for the most part and rests on inferences. In such cases, we must be careful not to substitute our judgment for the jury's; "[e]ven if we might have made contrary factual findings or drawn different inferences, we are not permitted to reverse the judgment if the circumstances reasonably justify those found by the jury." (People v. Perez, supra, 2 Cal.4th at p. 1126.)