Hepatitis in Rural Michigan,1968

ANSWERS

1.

  

Female

Male

Total

Younger

1%

1.5%

1.3%

Older

5%

8%

6%

Total

2.6%

2.8%

2.7%

Males are at roughly 1.5 (age-specific relative risk) times the risk of females, and older people are at roughly 5 (gender-specific relative risk) times the risk of younger people.

2. Roast Beef, because it has the strongest association with the disease (highest relative risk), and it explains most of the cases.

3. Soft-boiled eggs, because it has the strongest association with the disease (highest odds ratio), and it explains most of the cases.

4. A comparison of attack rates for the four possibilities using a control table shows that A affects incidence strongly but B does not, suggesting that A was contaminated but B was not.