Note Your answers to the questions below should follow the expectations for homework found here. Due date is on the Dates page.

Food Intake for Rainbow Trout

Hatchery Feeding Pirhonen and Koskela (2005) tested the hypothesis that food intake was significantly related to stomach volume for Rainbow Trout (Oncorhynchus mykiss). If this relationship exists, then stomach volume could be predicted by estimating food intake rather than sacrificing and dissecting the fish. Their experiment consisted of four groups of fish – those that had been starved for 1, 4, 8, or 16 days prior to being fed. In one aspect of their study they wanted to determine if the model for predicting stomach volume from food intake differed by starvation-length group.

  1. Construct indicator variable(s) such that the 1-day starved group is the reference group. [Note: Provide clear names for the variables and clearly define what 0 and 1 means for each.]
  2. Write the ultimate full model for an indicator variable regression with these data.
  3. Show all possible submodels that can be constructed from your ultimate full model.
  4. Carefully interpret the meaning of each parameter in your ultimate full model.
  5. Write the models in the null and alternative hypothesis for a parallel lines test.
  6. Write the models in the null and alternative hypothesis for an intercepts test (assuming that the lines are parallel).