11-03 · Explain a longitudinal result
Optional review after the two sessions on 18 November
No new essential method or advanced fitting is required. Use scripts or supplied outputs. Choose the steps below that help with the same project draft you will revise during Unit 12 follow-up.
- Review, 20 minutes: use the review deck and recap. Explain how factor time and continuous time differ, what the interaction means, and what the calf intercept supplies.
- Revisit evidence, 20–25 minutes: run
after-class-student.Ror read reference/output.txt. Compare the mean diet difference at 0, 4 and 8 weeks. State units, time point and uncertainty. Read the optional supplied AR(1) results and explain what assumption about repeated weights changes; fitting it is optional. - Project revision, 20–30 minutes: write 150–200 words describing what researchers do to the animals or groups and what they measure. Explain why the model suits those records, give one useful estimate with its uncertainty, describe one check and state a remaining concern. Record any justified change from your saved plan. Choose one alternative assumption to compare and explain why the study makes that comparison useful. Save a labelled draft figure. If your project has no repeated measurements, retain its own outcome type and groups instead of adding calf time terms.
Use any figure or paragraph you revise here in the draft you bring to the consulting clinic on 25 November. Your figure may remain provisional where data or model adequacy is unresolved; state that clearly.
Self-check
Researchers record week 0 before feeding starts. Why does the diet coefficient describe that starting comparison? How does uncertainty in expected weight differ from the variation in future individual weights? If a calf is ill and misses a visit, what should researchers investigate before deciding how to use its other weights?
Open the instructor-supplied Posit Cloud project for 11-longitudinal-data. All files are already provided in its project root. · Project launch and scope