Answer
.1574 to .1822
Work Step by Step
p = $\frac{x}{n}$ = $\frac{422}{2485}$ = .1698
$z_{a/2}$ = 1.645
p - $z_{a/2}$ $\times$ $\sqrt \frac{p(1-p)}{n}$ = .1698 - 1.645 $\times$ $\sqrt \frac{.1698(1-.1698)}{2485}$ = .1574
p - $z_{a/2}$ $\times$ $\sqrt \frac{p(1-p)}{n}$ = .1698 + 1.645 $\times$ $\sqrt \frac{.1698(1-.1698)}{2485}$ = .1822