I was wondering if my calculation is right for this question
A recent survey of 800 Irish households found that 74% of households have a fixed line telephone. Infer a 95% confidence interval for the percentage of the total population of Irish households that have a fixed line telephone.
N = 800
P = .74
Q = 1 - .74 = .26
√(.74*.26/800) = 0.015
95% Z_Score = 1.96
74+%/- 1.96 * 0.015 = 0.03
74%+/-3%
This looks good to me, including the numerical values. No need to report more digits.