Exercise 13-4 introduced you to an experiment to investigate the potential effect of consuming chocolate on cardiovascular health. The experiment was conducted as a completely randomized design, and the exercise asked you to use the ANOVA to analyze the data and draw conclusions. Now assume that the experiment had been conducted as an RCBD with the subjects considered as blocks. Analyze the data using this assumption. What conclusions would you draw (using α = 0.05) about the effect of the different types of chocolate on cardiovascular health? Would your conclusions change if α = 0.01?

Exercise 13-4

An article in Nature describes an experiment to investigate the effect on consuming chocolate on cardiovascular health (“Plasma Antioxidants from Chocolate,” 2003, Vol. 424). The experiment consisted of using three different types of chocolates: 100 g of dark chocolate, 100 g of dark chocolate with 200 ml of full-fat milk, and 200 g of milk chocolate. Twelve subjects were used, seven women and five men with an average age range of 32.2 ±1 years, an average weight of 65.8 ± 3.1 kg, and body-mass index of 21.9 ± 0.4 kg m−2. On different days, a subject consumed one of the chocolate-factor levels, and one hour later total antioxidant capacity of that person’s blood plasma was measured in an assay. Data similar to those summarized in the article follow.