



 
Hi Mini, The confidence limits for the proportion p a binomial distribution is
where n is the sample size. Since you want 98% confidence interval α is 0.02. Since the margin of error is 0.02 the bounds on the confidence interval are ±0.02. Since you have no previous estimate for p take p = 1/2. Set the bounds on the confidence limits above to ±0.02, substitute the values you know and solve for n. I hope this helps,  


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