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

Black Bear Weight

Black Bear Measuring the live body weight of large-bodied animals can be impractical when equipment needed to weigh individuals is inadequate or unavailable. Thus, the objective of Bartareau (2017) was to develop a model to accurately estimate the live body weight of Black Bears Ursus americanus floridanus in Florida based on the relationship between body weight as determined by a scale and sex, morphometric measurements (e.g., body length and chest girth), and age predictor variables that are more easily obtained in the field. Bartareau’s data are available in BlackBears.csv (download, meta). Use these data to determine if body weight can be predicted from body length for non-cub bears (i.e., older than one year of age). [Note that you will need to filter the raw data.] In doing so, answer the following questions.

  1. Perform a thorough analysis of assumptions.
  2. If needed, transform the data to meet the assumptions. Describe your process and show that the assumptions are adequately met on the new scale. [Note: I strongly urge you to first consider a transformation that is most often used with data such as these that tend to follow a power function relationship.]
  3. Describe whether a significant relationship exists between the two variables.
  4. If a significant relationship exists between the two variables, then carefully (and thoroughly) describe that relationship. [Make sure to include a plot that illustrates your description.]
  5. Demonstrate how your model can be used to predict the weight for a non-cub bear given its length (you can choose the length). [Note: Make sure to interpret the interval on the scale of interest to the researchers.]