Answer
The events are not independent because $P(3000~to~3999~grams~|~postterm)\ne P(3000~to~3999~grams)$.
Work Step by Step
$P(3000~to~3999~grams)=\frac{2,825,549}{4,305,340}=0.6563$
$P(3000~to~3999~grams~|~postterm)=\frac{175,221}{242,139}=0.7236$
$P(3000~to~3999~grams~|~postterm)\ne P(3000~to~3999~grams)$
So, the events are not independent (see definition on page 292).
