I don't know anything about statistics as a science, so I could be way off base, but it seems to me that baseball stats are more a measure of past performance rather than a predictor of the future, sort of like the difference between prophecy and prediction. Wouldn't you have to have more data than just hits vs at bats to predict how a particular human would react in a certain situation? And even then, giving the subjectiveness of human nature, would you have a huge +/- ?
statistical measurements will ALWAYS be descriptive. If used properly, they are used to identify and understand process/production inefficiencies etc... so that they may be corrected. I believe pharmaceutical manufacturers do "studies", but that involves far more than statistical measurements. Often times, going so far as to quantify expert opinions on effects of drugs etc...
In the end, it always boils down to past information used to make future decisions. In no way can past performance serve as a guarantee of future results. That would be as bad as the gambler's paradox of "being due". It's speculation, pure and simple. Consider it, at best, an educated guess.
I've come to the conclusion that Bill James has distanced himself from this organization for a reason, acknowledging when he was hired by the Red Sox that statistical analysis is only PART of the solution. You still have to have those expert opinions factored into the equation. Are all expert opinions equal? Absolutely not. Are the best experts ALWAYS right? Still, no. Anyway... I won't lie, I do enjoy reading the box scores and the stat lines from a game. I also like to watch the actual game. I've learned to identify things from the actual play on the field that I never understood, prior to joining this community. The one thing I will say, it has made sites like ESPN (or even ESPN on tv), FOX Sports Net, and other similar coverage very challenging to watch at times. I realize I'm only a novice/amateur baseball observer. But some of the national baseball guys (Joe Buck, I'm looking squarely at you) are just dimwits when it comes to baseball knowledge. So, it's not hard to understand why a stat head might get carried away with their absolute certainty. Not when the voices they hear are the morons given a microphone on the national level.