What sample size should be obtained if he wants to be within 4 percentage points with 96% confidence if he uses an estimate of 52% obtained from a poll?

E = Z* Sqrt {pq/N} e = 4% = 0.04; Z = 2.054 at 96% confidence, p= 52% = 0.052, q= 1-p = 1-0.52 = 0.48, N = Sample size required

Therefore,
N = (e/Z)^2*pq = (2.054/0.04)^2*0.52*0.48 = 658.15 ≈ 659 respondents