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Frequency distribution of the number of episodes of tonsilitis per year for the matched pair case-control study.
| Number of episodes of tonsillitis per year |
Frequency (N) | Percent (%) |
|---|---|---|
| Subjects in case group (N = 10) | ||
| 1 | 4 | 40 |
| 2 | 1 | 10 |
| 6 | 1 | 10 |
| Not applicable | 4 | 40 |
|
| ||
| Subjects in control group (N = 10) | ||
| 1 | 2 | 20 |
| Not applicable | 8 | 80 |
