Table 3 Calculations for the log-rank test to compare treatments for the data in Table 1
Survival time (days) | Treatment group | Number known to be alive (ri) | Deaths (di) | Risk for death (di/ri) | Number known to be alive from treatment group 2 (r2i) | Expected number of events in treatment group 2 (E2i) |
|---|---|---|---|---|---|---|
0 | ||||||
1 | 2 | 15 | 2 | 2/15 = 0.133 | 8 | 8 × 0.133 = 1.07 |
1 | 2 | |||||
4 | 2 | 13 | 1 | 1/13 = 0.077 | 6 | 6 × 0.077 = 0.46 |
5 | 2 | 12 | 1 | 1/12 = 0.083 | 5 | 5 × 0.083 = 0.42 |
6+ | 2 | 11 | 0 | 0/11 = 0 | 4 | 4 × 0 = 0.00 |
8 | 1 | 10 | 1 | 1/10 = 0.100 | 3 | 3 × 0.100 = 0.30 |
9 | 2 | 9 | 1 | 1/9 = 0.111 | 3 | 3 × 0.111 = 0.33 |
9+ | 2 | 8 | 0 | 0/8 = 0 | 2 | 2 × 0 = 0.00 |
12 | 1 | 7 | 1 | 1/7 = 0.143 | 1 | 1 × 0.143 = 0.14 |
15+ | 1 | 6 | 0 | 0/6 = 0 | 1 | 1 × 0 = 0.00 |
22 | 2 | 5 | 1 | 1/5 = 0.200 | 1 | 1 × 0.200 = 0.20 |
25+ | 1 | 4 | 0 | 0/4 = 0 | 0 | 0 × 0 = 0.00 |
37 | 1 | 3 | 1 | 1/3 = 0.333 | 0 | 0 × 0 = 0.00 |
55 | 1 | 2 | 1 | 1/2 = 0.500 | 0 | 0 × 0 = 0.00 |
72+ | 1 | |||||
E2 = 2.92 |