A Researcher Tests Whether There Is Any Difference Between How

Multiple Choice

A researcher tests whether there is any difference between how fast people work in the morning versus how fast they work in the evening. What is the NULL hypothesis?

A) People who work in the morning work faster.
B) People who work at night work faster.
C) There is some difference, but which is faster is not predicted.
D) There is no difference in the speed at which people work.