David B. answered 04/25/21
Math and Statistics need not be scary
Using a beta distribution the answer is
This is the correct, unbiased, exact solution.
Normal approximation is close... The answer is b
note: for normal aproximation you need n (675), p(1/3), q(2/3) and the proper critical Z value for two sided 99% Confidence) Zcrit = 2.576. Then follow the standard formula for CI of a proportion.