Answer
P(p̂ < 0.5) = 0.3228. This implies that about 32 out of 100 samples of size 500 contain 38% or fewer Americans who believe marriage is now obsolete.
Work Step by Step
Using data from part a for p̂ < 0.38, we have:
$z = \frac{0.38 - 0.39}{0.022} = -0.46$
P(p̂ < 0.5) = P(z < -0.46) = 0.3228
