Note: Your answers to the questions below should follow the expectations for homework found here. Questions outside of class can be asked on the Module Assignments-Questions Teams channel (see link on homepage).

Turtle Nesting Ecology

In this, this, and this previous exercises you prepared variables required of an IVR, identified an ultimate full model and related sub-models, interpreted model parameters, an performed hypothesis tests. Continue with those analyses to answer the questions below.

  1. Thoroughly check all assumptions on the original scale.
  2. If appropriate, identify a transformation for which the assumptions are met (and show that they are met). If no transformation is needed or no transformation is better than the original scale than say so.
  3. If appropriate, identify (and provide evidence for) which groups have different slopes. If not appropriate, than say so (and explain why). You may need to refer back to your parallel lines test from the previous exercise.
  4. If appropriate, describe the difference in slopes for the two groups that are most different. Make sure to use a confidence interval.
  5. If appropriate, identify (and provide evidence for) which groups have different intercepts. If not appropriate, than say so (and explain why). You may need to refer back to your coincident lines test on the previous exercise.
  6. If appropriate, describe the difference in mean (back-transformed?) clutch size for the mean (back-transformed?) curved carapace length for the two groups that are most different. Make sure to use a confidence interval.
  7. If appropriate, describe the difference in mean (back-transformed?) clutch size for the mean (back-transformed?) curved carapace length for the two groups that are least different (whether significantly different or not). Make sure to use a confidence interval.
  8. Is the mean (back-transformed?) clutch size at the maximum (back-transformed?) curved carapace length different between turtles from the Indian Ocean and West Atlantic regions? Provide evidence and an explanation for your answer.

 

Water Quality Near a Gold Mine

In this, this, and this previous exercises you prepared variables required of an IVR, identified an ultimate full model and related sub-models, interpreted model parameters, and performed hypothesis tests. Continue those analyses by answering the questions below.

  1. Thoroughly check all assumptions on the original scale.
  2. If appropriate, identify a transformation for which the assumptions are met (and show that they are met). If no transformation is needed or no transformation is better than the original scale than say so.
  3. If appropriate, identify (and provide evidence for) which groups have different slopes. If not appropriate, than say so (and explain why). [Note that if you transformed your data here then you will need to perform a parallel-lines test that is different than what you did last exercise.]
  4. If appropriate, describe the (back-transformed) “difference” in slopes for the two groups that are most different. Make sure to use a confidence interval.
  5. If appropriate, describe the (back-transformed?) “difference” in slopes for the two groups that are least different (whether significantly different or not). Make sure to use a confidence interval.
  6. Interpret the (back-transformed?) slope for the total phosphrous group.
  7. If appropriate, identify (and provide evidence for) which groups have different intercepts. If not appropriate, than say so (and explain why). [Note that if you transformed your data here then you will need to perform a parallel-lines test that is different than what you did last exercise.]
  8. If appropriate, describe the difference in mean (back-transformed?) phosphorous level for the mean (back-transformed?) distance from the gold mine for the two groups that are most different. Make sure to use a confidence interval.