Recruiting Olympic-caliber athletes gets harder the more you need per condition.
| Reps in cell | Cost per rep |
|---|---|
| 1 - 5 | $500 |
| 6 - 10 | $750 |
| 11+ | $1,000 |
◆ THE BLUEPRINT
Experimental Design Concepts
Replication
Each observation in a cell is a replicate. More replicates means better estimates of within-cell variability and more statistical power to detect effects.
Factorial Design
A 2x2 factorial has 4 cells. A 2x2x2 has 8 cells. At a fixed budget, adding factors doubles the cells and halves the reps per cell.
Blocking
A generalized block design groups experimental units by a known source of variability (e.g., player position). The block term absorbs that variability, reducing SSE and increasing F-statistics for the treatment effects.
The ANOVA Model
Without blocking:
With blocking by Position: