ERA means what?

One of the reasons Jeremy Hellickson won Rookie of the Year was his ERA. 

So what does ERA mean you ask? 

Well ladies (and gents) ERA refers to earned run average.  In baseball statistics, earned run average (ERA) is the mean of earned runs given up by a pitcher per nine innings pitched. It is determined by dividing the number of earned runs allowed by the number of innings pitched and multiplying by nine. Runs resulting from defensive errors (including pitchers' defensive errors) are recorded as unearned runs and are not used to determine ERA. (thank you Wikipedia).

So basically the lower this number is the better a pitcher is and thus resulting in more wins!!! So the fact that Hellickson's was 2.95 is pretty sweet!!!!