And the winner is...

Dave and Katie B!

Final stats for Andrew:

gestational age: 39 weeks, 4 days
weight: 7 lbs., 10 oz.
time to spare: almost exactly 3 hrs.

Dave gets points for guessing the closest gestational age (39 weeks, 6 days, which would have been Saturday), plus extra nerd points for his equation.  But Katie was spot-on for both the birth weight and the time at the hospital!  Way to go!  Your imaginary bags of marshmallows are in the mail. :)