Three year stats

Ok, so this is a little random but is something I've been thinking about. At two, Sarah and Matthew were close to the same weight and height and Megan was three pounds heavier and two inches taller. At three, Sarah and Megan were close to the same weight and height and Matthew was about 4 pounds lighter and 2 inches shorter. What does this mean? Sarah had a huge growth spurt between 2 and 3--she put on about 7 pounds and grew 4 inches! Megan and Matthew both grew about 2-2.5 inches and put on between 3-3.5 pounds so Sarah was close to double. So much for Sarah being the littlest one. At three, she actually weighed the most out of any of the kids. That's crazy!