A sports scientist wants to compare the effectiveness of two endurance training protocols, Protocol X X\,X and Protocol YYY, using a sample of 60 runners. They adopt an independent groups design where 30 runners will perform Protocol X X\,X and the other 30 will perform Protocol YYY.
Explain why the scientist should use random allocation to assign the runners to the two protocols.
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.