Below is a diagram of a study of three fertilizers comparing yields between two soil types.
Which of these is the blocking variable in this design?
- A
Yield
- B
Plot area
- C
Fertilizer (F1, F2, F3)
- Dcheck_circle
Soil type (sandy vs clay)
Explanation
The blocking variable groups experimental units; here plots are first divided by soil type before treatments are assigned. Fertilizer is the factor of interest, not the block.