Think about an interval that covers the entire spread of the data... you can be 100% confident that it contains the true mean. If you have a very narrow range (e.g. 115.1 mph to 115.2 ...
True, essays usually give you a choice of 2 sides, and asks which one you 'prefer' or think is the best of both, and to defend your side, and "bash down" the other one
