1. Math
2. Statistics And Probability
3. the investigators administered the study questionnaire by telephone from march...

# Question: the investigators administered the study questionnaire by telephone from march...

###### Question details

The investigators administered the study questionnaire by telephone from March 15-23. Students selected for participation were called at their dormitory room or their home telephone number as recorded in university records. If the student was not present at either location but information on his/her whereabouts was available, additional phone calls were made to contact the student. Students not reached during spring break were interviewed on their return to the university.

Thirty-six cases and 144 controls were contacted. Cases included in the study were similar to all cases with respect to gender, age, and year in college. Their dates of onset of illness had a distribution similar to that seen in Figure 1.

Results from the unmatched case-control study were tabulated by TDH and CDC epidemiologists. Only persons who ate at the main cafeteria for the specified period were included in the meal-specific analyses. (Table 2)

Table 2. Risk factors for illness among persons eating at the main cafeteria, unmatched case-control study, University X, Texas, March 9-10, 1998.

 Exposure Ill exposed/ Total ill Well exposed/ Total well Measure of association p-value Ate at salad bar - lunch March 9 9/30 36/100 Ate at salad bar - dinner March 9 5/18 15/59 Ate at salad bar - lunch March 10 6/28 23/96 Ate at salad bar - dinner March 10 6/15 12/44 Ate at salad bar* 13/19 49/69 Ate at deli bar - lunch March 9 18/30 12/101 Ate at deli bar - dinner March 9 7/18 5/61 Ate at deli bar - lunch March 10 13/29 12/96 Ate at deli bar - dinner March 10 4/16 4/44 Ate at deli bar* 28/36 20/116

Question 20: Calculate the appropriate measure of association for these exposures. Interpret the results.

HI! What is the formula for measuring association?