The document outlines a presentation analyzing a dataset on the number of eggs fished along coastal areas. It examines Poisson, zero-inflated Poisson (ZIP), and hurdle models to predict egg counts. The best model was found to be ZIP, which accounts for excess zeros in the data. Predictions using this model suggest it could be useful for estimating egg counts in other regions like Ireland and Spain.

1. Francesco Donelli
Giuseppe Giadone
Alessandro Esposito
Francesco Esposito

2. Outline of
the
presentation
Our dataset and goal of the analysis
Nature of the data and Poisson model
Zeros inflation and ZIP model
Model selection and predictive power
Final considerations

3. Goal of the analysis and content of the
dataset
 Goal: finding a good model with respect to both predictive power and model validation
criteria.
 Content: records about the number of eggs fished through the coasts of England, France and
Ireland.
 Variables:
• Egg count: number of eggs fished [response variable];
• Time: recording time;
• Flow: power of sea currents;
• C.dist: distance from sample to 200m contour (degrees);
• Salinity;
• S.depth: sampling start depth;
• Temp.surf: sea temperature;
• Net area: sampling net area.

4. Why remove latitude and longitude?

5. COLLINEARITY TEST OF THE
VARIABLES

6. Poisson model

7. SUMMARY OF THE POISSON MODEL

8. RESIDUALS vs FITTED

9. • Check for Leverages • Check for Outliers • Check for Influential Points

10. HOW MANY ZERO?

11. Hurdle or ZIP?

12. ZIP Model

13. SUMMARY OF THE ZIP MODEL

14.  VALUE OF AIC WITH ALL VALUES OF
FLOW

15. VALUE OF MSE WITH ALL VALUES OF
FLOW

16. EFFECTS OF FLOW

17. NEW SUMMARY OF THE MODEL

18.  PLOT OF AIC WITHOUT HIGH VALUES
OF FLOW

19.  PLOT OF MSE WITHOUT HIGH VALUES
OF FLOW

20. Final conclusions (ZIP model)

21. WHO NEEDS OUR MODEL?
Egg count

22. EGG COUNT PREDICTED FOR
IRLAND AND SPAIN

23. THANKS FOR
ATTENTION

24. APPENDIX
Vuong test (zip is model 1)

25. Ocount: actual zeros
Pcount: predicted zeros

26. • Python code used to
implement the maps

27. Python code used to
create graphics in Final
conclusion slides

28. Poisson model residuals

29. ZIP model residuals vs fitted

30. Hurdle model