Given the following experiment: Male Albino laboratory rats are used routinely in many kinds of experiments. Proper nutrition for the rats is important. Specifically, this experiment examines the amount of protein in the diet and the amount of threonine in the diet. The general protein in the diet is threonine deficient. There are three levels of threonine (0.3, 0.6, 0.9% of diet) and three levels of protein (12, 17, and 21% of diet), for a total of 9 treatments. Gender was a potentially significant factor but the researcher was not interested to compare between males and females. She considered 180 male rats. Those rates were all weighed and separated into five groups of 36 of approximately uniform weight (Weight at time zero). The rats in each group were randomly assigned to each of the nine treatments (one treatment per group). Rats’ body weights were measured three more times: after one, two and three months.
A) Answer the following:
i) What is the response variable?
ii) List the factors in this study and their levels
iii) What factor(s) was used as a blocking factor?
iv) What nuisance factor(s) that was held constant?
B) How many observations in this experiment? Since the error is a function of subjects (rats): Error (factor (Subject)). What is the degree of freedom for the residuals?
C) What kind of experimental design used in this experiment? List the between block verses within block nuisance factors for this experiment.
D) Draw the experiment design starting with the benchmark. Label each part along with its degrees of freedom.