The average speed of a volleyball serve is 57 miles per hour. Natalie practiced a new technique to improve her serving speed. Her coach recorded the speed of 36 random serves during practice and found that her average speed using the new technique was 58.9 miles per hour, with a standard deviation of 2.8 miles per hour.

Part A: State the correct hypotheses if Natalie is trying to prove the new technique is an improvement over the old technique.

Part B: Identify the correct test and check the appropriate conditions.