Following up on my earlier Fanshot, here's a look at the temperature's affect on Jhonny Peralta vs. the rest of the AL. At Jay's request, I looked at batting average, BB/K, and OPS.
I took Retrosheet's AL data from 2003 (the year Peralta entered the league) to 2008. Here's how the American League fared in terms of batting average:
and here's how Peralta fared:
In care they're hard to see, the AL had an r-squared of .47 and Peralta an r-squared of .18. Not much, but they're both positive. I also had Excel give me the equation for the trendlines:
AL: average = 0.0007*temperature + 0.2202
Peralta: average = 0.0028*temperature + 0.0484
If I'm interpreting that correctly (and there's no guarantee I am), that means the temperature has four times the affect on Peralta as is does the average AL hitter.
Next. here's BB/K for the AL:
and for Peralta:
The AL graph had a distinctive curve to it, so I decided to fit a polynomial trendline. As you can see, the average AL hitter's BB/K ratio improves in extreme temperatures, while Peralta's gets worse. I'm not sure what, if anything, that means.
Finally, here's a look at the AL OPS:
The AL had an r-squared of .39 and Peralta .06. The line equations are:
AL: OPS = 0.0017*temperature + 0.636
Peralta: OPS = 0.0042*temperature + 0.4071
This time - again, if I'm interpreting things correctly - the temperature has 2.5 times the influence on Peralta's OPS as it has on the average AL hitter's.