Chapter 9 - Section 9.1 - Assess Your Understanding - Applying the Concepts - Page 438: 43

Lower Bound = 0.018, Upper Bound = 0.316

Here x = 2, n = 20, α = 0.05, $z_{0.025} = 1.96$ $\tilde p = \frac{2 + 2}{20+4} = 0.167$ Lower Bound = $0.167 - 1.96 . \sqrt \frac{0.167 (1-0.167)}{20+4} = 0.018$ Upper Bound = $0.167 + 1.96 . \sqrt \frac{0.167 (1-0.167)}{20+4} = 0.316$