A researcher testing a new fertilizer believes that yields differ between sandy and clay soil plots. She separates her 40 plots into 20 sandy and 20 clay plots, and within each soil type randomly assigns half to receive the new fertilizer and half to receive the standard fertilizer.
Which experimental design is described?
- A
Observational study
- Bcheck_circle
Randomized block design
- C
Matched-pairs design
- D
Completely randomized design
Explanation
Plots are grouped into blocks (soil type) thought to affect yield, and treatments are randomly assigned within each block. This is a randomized block design.