Blocking

Lyrics © Mary McLellan 
may sing to the tune of The Beach Boys "Good Vibrations" 

I see you have a trait there
That may affect the way subjects respond
I see you have a trait there
That may affect the way subjects respond
What do you do
Make homogeneous groups
What do you do
Make homogeneous groups

Blocking reduces variation
Blocking reduces variations
Within each block is experimentation
Within each block is experimentation