Table 4 Comparison of frequency distributions between two breast cancer groups, by date of first employment
From: Increased standardized incidence ratio of breast cancer in female electronics workers
| Â | Date of First Employment | |||||
|---|---|---|---|---|---|---|
| Â | Before 20 June 1974 (n = 90) | After 20 June 1974 (n = 196) | ||||
| Â | Mean | SD | Range (years) | Mean | SD | Range (years) |
Age at Diagnosis | 44.3 | 7.1 | 31–70 | 42.6 | 6.9 | 30–63 |
Age at First Employment* | 19.6 | 6.1 | 14–46 | 22.4 | 6.3 | 14–43 |
Length of Employment* | 7.8 | 7.5 | 0.005–25 | 4.8 | 6.5 | 0.008–18.5 |