You want to obtain a sample to estimate the percentage of college students in the U.S. that get a GPA of least 2.5. You would like to be 95% confident that your estimate is within 3% of the true...

You want to obtain a sample to estimate the percentage of college students in the U.S. that get a GPA of least 2.5. You would like to be 95% confident that your estimate is within 3% of the true population proportion. You have no reasonable estimate for the population proportion. You do not know the number of college students in the U.S., but you know it’s very large. How large of sample size is required?