Research Methodology · Hypothesis Testing

Which of the following statements about directional and non-directional tests are correct? 1. One-tailed tests generally have more statistical power in the specified direction than two-tailed tests. 2. Two-tailed tests can detect differences in both positive and negative directions. 3. A one-tailed test intrinsically increases the overall risk of a Type I error compared to a two-tailed test if α is held constant. 4. A one-tailed test requires a pre-specified directional hypothesis. 5. Two-tailed tests allocate α/2 of the critical region to each tail of the distribution.