A political candidate has asked you to conduct a poll to determine what percentage of people support him. If the candidate only wants a 1.5% margin of error at a 99% confidence level, what size of sample is needed

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)