A farmer wishes to determine which of two brands of baby-pig pellets, Kent or Moormans, produces better weight gain. Two of his sows each give birth to litters of 10 pigs on the same day, so he decides to give the baby pigs in litter A only Kent pellets, while the pigs in litter B will get only Moormans pellets. After four weeks, the average weight gain for pigs in litter A is greater than the average weight gain for pigs in litter B. The feed they get is not the only factor affecting the rate at which pigs gain weight. Genetic differences also affect weight gain. It is likely that the pigs in litter A are genetically different from the pigs in litter B since the two litters have different mothers.
What experimental design technique could the farmer use to take into account the genetic differences?
A) Placebo
B) Blocking
C) Probability sampling
D) Double blinding
E) Observational study

Question

Quizplus · Accepted Answer

Blocking involves grouping individuals based on certain characteristics that may affect the outcome of the experiment, in this case genetic differences. By separating the litters into two groups based on their mothers, the farmer can control for any possible genetic variations that may influence the weight gain of the pigs.

A Farmer Wishes to Determine Which of Two Brands of Baby-Pig