Answer
Since we fail to reject the Null Hypothesis, there is insufficient evidence that the percent of registered voters is more than 42% Republican.
Work Step by Step
$H_{o}$: p = 0.42, $H_{a}$: p > 0.42, n = 320, α = 0.05
1 - α = 0.95 , $z_{0.95} = 1.645$
p̂ = 142/320 = 0.4437
$z = \frac{0.4437 - 0.42}{\sqrt \frac{0.42 (1-0.42)}{320}} = 0.86$
0.86 < 1.645: We fail to reject the Null Hypothesis.
