Confidence Intervals, Proportion Estimations
In a study of perception, 107 men are tested and 24 are found to have red/green color blindness.
(a) Find a 92% confidence interval for the true proportion of men from the sampled population that have this type of color blindness.
(b) Using the results from the above mentioned survey, how many men should be sampled to estimate the true proportion of men with this type of color blindness to within 2% with 98% confidence?
(c) If no previous estimate of the sample proportion is available, how large of a sample should be used in (b)?
I have already answered (a). However, I am at a complete loss as to how to answer (b) or (c). For one thing, I am not quite sure what (b) is even asking. Advice on this question would be greatly appreciated.