In an experiment to investigate the effects of different soil nutrient amendments on pomegranate fruit yield (number of fruits per tree) researchers first selected 24 crop rows within a pomegranate farm to follow the irrigation lines. Nine trees in each row were selected and were randomly assigned one of three soil nutrients (three trees per nutrient): potassium, KNO3; magnesium, MgS04; or zinc, ZnS04. All of the fruit from each the treated trees were counted. In all 216 trees (24 × 9) were observed.17
(a) Identify the blocking, treatment, and response variables in this study.
(b) Why do you think the blocks were chosen in the way they were in this study?
(c) What were the researchers hoping to accomplish by using blocks?
(d) If it is found that there are statistically significant differences between the mean number of fruits produced across the treatments, will the design of this study allow the researchers to conclude that the nutrients contribute to this difference?