New varieties of corn with altered amino acid content are being investigated for higher nutritional content. The two new varieties, opaque-2 and floury-2, were to be compared to the normal corn. Also different levels of protein in the diet were made up by mixing each corn type with soybean. There are three protein levels, 12% or 16% or 20%, to be tried.
A large trial is to be undertaken with one-day-old chicks to be fed the meals. The chicks' weight gains are to be measured after 21 days on their assigned diet.
a) Name all the explanatory and response variables in this study.
b) Outline a randomized comparative experiment for this study, clearly describing all of the three important features needed in any well-designed experiment.