More rain for California? The changing climate will probably bring more rain to California, but we don’t know whether the additional rain will come during the winter wet season or extend into the long dry season in spring and summer. Kenwyn Suttle of the University of California at Berkeley and his coworkers wanted to compare the effects of three treatments:

added water equal to 20% of annual rainfall either during January to March (winter) or during April to June (spring), and no added water (control). Eighteen plots of open grassland, each with area 70 square meters, were available for this study. One response variable was total plant biomass, in grams per square meter, produced in a plot over a year.37 Describe a completely randomized design for this experiment. Write a few sentences describing how you would implement your design.