Refer to Practice Problem 3.

a. Write a complete model statement for a linear model to fit to the penguin data. Indicate what each term in the model represents.

b. What are the null hypotheses tested in the ANOVA table for the linear model?

c. What are the assumptions of your analysis?

Data from Practice Problem 3

A study of the Magellanic penguin (Spheniscus magellanicus) measured stress-induced levels of the hormone corticosterone in chicks living in either tourist-visited areas or undisturbed areas of a breeding colony in Argentina (Walker et al. 2005). Chicks at three stages of development were included in the study—recently hatched, midway through growth, and close to fledging. Penguin chicks were stressed by being captured by the researchers and their corticosterone concentrations were measured 30 minutes later. The following graph diagrams the mean hormone concentrations for the three age groups of chicks from tourist-visited (filled circles) and undisturbed (open circles) areas of the colony.