Answer
Lower Bound = 0.215
Upper Bound = 0.285
Work Step by Step
x = 256, n = 1024, $\hat p = 0.25$, α = 0.01, z = 2.5758
$E = 2.5758 \times \sqrt \frac{0.25 (1-0.25)}{1024} = 0.035$
Lower Bound = 0.25 - 0.035 = 0.215
Upper Bound = 0.25 + 0.035 = 0.285
