Discussion:
Q: Suppose that in a brand-preference survey you want to estimate the proportion of consumers who prefer your company's organic milk versus normal milk to within 0.03 with 95% confidence. This means that when the sample is taken and the calculations completed the interval estimate is to be p^±0.03.
• Write the formula for the sample size n, as a function of p^.
• If you have no knowledge of even the approximate values of p^ , what value would you choose for it? Justify your answer.
• If you believe that p will turn out to be approximately 0.2, how much would n be?