A researcher is interested in determining the proportion of first year university students who have suffered hearing loss from loud music and other big-city sounds. How many students should she give hearing tests to in order to determine this proportion with a margin of error (half width of confidence interval) of .075 using a 95% confidence interval?
a) If she believes from previous studies that the true proportion is .25. (Give answer as a whole number )
b) If she has no idea of the proportion with hearing loss. (Give answer as a whole number.)