A study testing two fertilizers on tomato yield groups plots by soil type, then randomly assigns fertilizers within each group. This is
- A
A completely randomized design
- B
A matched-pairs design
- Ccheck_circle
A randomized block design — soil is the blocking variable
- D
A stratified survey
Explanation
Blocking on a known nuisance variable (soil) reduces unexplained variation, sharpening the comparison between fertilizers within each block.