Using a computer software program, the epidemiologists have analyzed the food history data from the questionnaires and have constructed the following attack rate table.
ATTACK RATE TABLE:
|
FOOD ITEMS
|
PERSONS WHO ATE SPECIFIED FOOD
|
PERSONS WHO DID NOT EAT SPECIFIED FOOD
|
95% Confidence Interval
|
|
Ill
|
Not Ill
|
Total
|
Attack Rate
|
Ill
|
Not Ill
|
Total
|
Attack Rate
|
|
Chicken
|
36
|
30
|
66
|
55%
|
4
|
30
|
34
|
12%
|
1.2 - 17.7
|
|
Potato Salad
|
32
|
40
|
72
|
44%
|
8
|
20
|
28
|
29%
|
0.6 - 3.9
|
|
Potato Chips
|
20
|
4
|
24
|
83%
|
20
|
56
|
76
|
26%
|
1.8 - 5.7
|
|
Ice Cream
|
24
|
0
|
24
|
100%
|
16
|
60
|
76
|
21%
|
2.6 - 8.8
|
|
Pie
|
32
|
4
|
36
|
89%
|
8
|
56
|
64
|
13%
|
2.8 - 18.0
|
|
Pepsi
|
36
|
40
|
76
|
47%
|
4
|
20
|
24
|
17%
|
0.8 - 10.5
|
- Calculate the relative risk for each of the food items.
- Identify the food items that have a statistically significant confidence interval.
- Identify the food item that is the most likely source of transmission. Explain.