The Art of Statistics

the overall rate for all births in the US in 2013 was 8%, while the rate in black women was 13%, a notable difference between races.

shows that we would expect 1.7% of babies in this group to be low birth weight – in fact the actual number was 14,170 (1.3%), in close agreement with the prediction from the normal curve.

medical rather than statistical reasons, babies below 2,500 g are considered ‘low birth weight’, and those below 1,500 g ‘very low birth weight’.