Bear spray, easily reachable on one's person, will be much more effective than a pistol. But data-wise, you have to consider that most near-misses probably are

Bear spray, easily reachable on one's person, will be much more effective than a pistol. But data-wise, you have to consider that most near-misses probably aren't reported, that successfully defended attacks may not even be reported, and that people in certain environments will have a much greater risk than the average.