3. 2

4. Variable: any characteristic, number, or attribute that can be measured or counted Numeric variables have values that describe a measurable quantity as a number, like 'how many' or 'how much' May take any real number value (continuous) or only whole number values (discrete) The data collected for a numeric variable are quantitative data 3

5. Variable: any characteristic, number, or attribute that can be measured or counted Categorical variables have values that describe a 'quality' or 'characteristic' of a data unit, like 'what type' or 'which category' Categories should be mutually exclusive (in one category or in another) and exhaustive (include all possible options) May have a natural order (ordinal) or not (nominal) The data collected for a categorical variable are qualitative data 4

6. Source: Australian Bureau of Statistics, 2013 5

7. Source: The Association of Faculties of Medicine of Canada (2013), CDC (2013) http://phprimer.afmc.ca/inner/primer_contents 6

8. Source: The Association of Faculties of Medicine of Canada (2013), CDC (2013) http://phprimer.afmc.ca/inner/primer_contents 7

9. 8

10. Source: The Association of Faculties of Medicine of Canada (2013) http://phprimer.afmc.ca/inner/primer_contents 9

11. Host = Pedestrians Agent = Kinetic Energy Environment = Physical & Sociocultural Vector = Vehicles 10

12. Source: The Association of Faculties of Medicine of Canada (2013) http://phprimer.afmc.ca/inner/primer_contents 11

13. 12

14. 13

15. 14

16. Source: The Association of Faculties of Medicine of Canada (2013) http://phprimer.afmc.ca/inner/primer_contents 15

17. 16

18. Source: The Association of Faculties of Medicine of Canada (2013) http://phprimer.afmc.ca/inner/primer_contents 17

19. Source: The Association of Faculties of Medicine of Canada (2013) http://phprimer.afmc.ca/inner/primer_contents 18

20. 19

21. HostAgent or vector Physical environment Sociocultural environment Pre-event Event Post-event 20

22. 21