Which hypothesis tells us whether a test is one-tailed or two-tailed?
Correct answer D. None of these
Explanation
The alternative hypothesis decides the tails: a statement such as μ ≠ μ0 gives a two-tailed test, while μ > μ0 or μ < μ0 gives a one-tailed test. It is not among the listed options.
Answer checked How we write and check questions
Discussion