Are Rosalie and Jasper the left-handed, or are Jacson and Nikki the ones?

I ask because if you look closely in the baseball scene, they bat with the position of a left-handed batter/hitter that is, when facing the pitcher, the left hand is the one more far away from the pitcher; so since Rosalie and Jasper have that same position, I got to the conclucion that they were left-handed (except Jasper that I think he's ambidextrous).
But are Nikki and Jackson too. I'm I in the right conclucion?