It's not an actual real numbers translation. "Expected" goals is just a guess. That said the Canes 5v5 juggernaut, 9th in xGF% (53.65), scored 4 more 5v5 goals than the Rangers, 16th in xGF% (50.15), over 82 games. Carolina was expected to score 194 goals to the Rangers 167. Carolina really scored 171 to the Rangers 167.
Now you're gonna hear that the Canes are just unlucky and the Rangers squeaked into the playoffs because they got lucky in 1 goal games.