Blocking in Experimental Design
Blocking divides experimental units into homogeneous groups (blocks) before randomization. Treatments are randomly assigned within each block. This controls for variation due to block characteristics, improving test sensitivity.
Real World
A sports science study at Loughborough University testing recovery drinks blocks participants by fitness level (elite, club, recreational) so that baseline fitness doesn't confound drink comparisons.
Exam Focus
State that blocking removes known variation from the error term, making it easier to detect genuine treatment differences.
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