An agricultural researcher is investigating the effect of a new bio-stimulant (derived from marine microalgae) on the shoot length of hydroponically grown rocket (Eruca sativa).
Formulate both a directional (one-tailed) hypothesis and a non-directional (two-tailed) hypothesis for this study, and distinguish between them by explaining the circumstances under which the researcher would choose to use a directional hypothesis rather than a non-directional hypothesis.
689 exam-style questions on AQA A Level Psychology Scientific processes. Each one has a worked solution and a mark scheme showing where the marks go.