So, basically what that is saying, is that, given his 2010 stats in 171 AB's, you can be 95% confident that over the course of 550 AB's, he would hit anywhere from:
BA - .277 to .296
Doubles - 40 to 50
HR - 24 to 34
RBI's - 72 to 82
SLG% - .482 to .573