Suppose that we want to estimate what percentage of all drivers exceed the 50 km/h speed limit on a certain stretch of road. (a) How large a sample will we need to be at least 99% confident that the...

Extracted text: Suppose that we want to estimate what percentage of all drivers exceed the 50 km/h speed limit on a certain stretch of road. (a) How large a sample will we need to be at least 99% confident that the error of our estimate, the sample percentage, is at most 3.5% ? (b) How large a sample will we need if we know that 20% of the drivers in a preliminary sample exceed the 50 km/h speed limit on that stretch of road.