Final answer:
To answer John Doe's question, he should perform a z-test.
Step-by-step explanation:
To answer John Doe's question of whether he has seen more zombie movies than the average American, he should perform a z-test. A z-test is used when a single population mean is being tested, and the population standard deviation is known. In this case, John knows the sample size (X) is 100, the population mean is 10, and the standard deviation is 5.