That's not completely accurate either. If you're going to compare HRs at Target Field vs. every other park, you need to break out every park. Because now you're comparing one hitters park to the average of all other parks. But hitter friendly parks (as well as other pitcher's parks) will skew the data. The only way that the data won't get skewed is if the park factors equaled out, which they don't. So, say a team like the Yankees play in a division where they see a lot more hitter's parks (which I don't know off of the top of my head, but I believe this is true), their HRs are going to be greatly skewed to show they hit way more HRs in other parks besides TF. I know you're trying to average it out per game, but it doesn't really matter. Your data is getting confounded. Sorry for the rant. This is just a statistics issue for me. They are a wonderful thing, but if you look at them incorrectly, they can lead you to the wrong conclusion. I'm probably not conveying my message very clearly either. This might be a good blog post though...