S2.4.5 - One-tailed and two-tailed tests

One-tailed and two-tailed tests.

Use one-tailed and two-tailed tests to connect the rule to the data and decision in the question.

This matters because one-tailed and two-tailed tests determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply one-tailed and two-tailed tests to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: One-tailed and two-tailed tests is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.