Table 4 Analysis of relationship between the numbers of meals in school and disease onset among cases from November 18 th - 22 nd , 2012
Category variables | Cases | Total | Attack rate (%) | Chi-square | P-value |
|---|---|---|---|---|---|
Grade (n = 164) | |||||
1-6 | 133 | 831 | 16.0 | 76.43 | <0.001 |
7-9 | 27 | 594 | 4.5 | ||
10-12 | 4 | 268 | 1.5 | ||
Meals (n = 180) | |||||
Had 3 meals | 146 | 1277 | 11.4 | 9.26 | 0.002 |
Only had lunch | 34 | 538 | 6.3 | ||
Boarding or not (n = 164) | |||||
Boarding | 142 | 1373 | 10.3 | 3.57 | 0.06 |
Not boarding | 22 | 320 | 6.9 |