
Brian L. answered 09/15/23
Board Certified Oncology Pharmacist and Pharmacotherapy Specialist
Make the assumption that the population proportion is 0.5. This maximizes the standard deviation of the sampling distribution of the sampling proportion (i.e. standard error), which is calculated as √(pq÷n).
The critical z-value for a 99% confidence interval is 2.576. You can now solve for the sample size n
2.576 = 0.01/√(0.5 × 0.5 ÷ n)
n = 16590