|
Calculations for the Kaplan–Meier estimate of the survival function for the treatment 2 data from Table 1 |
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| Patient number |
Survival time (days) |
Number known to be alive (ri) |
Deaths (di) |
Proportion surviving (pi) |
Cumulative proportion surviving (S [t]) |
|
|
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| 0 |
1 |
||||
| 1 |
1 |
8 |
|||
| 2 |
1 |
8 |
2 |
(8 - 2)/8 = 0.750 |
1 × 0.750 = 0.750 |
| 3 |
4 |
6 |
1 |
(6 - 1)/6 = 0.833 |
0.750 × 0.833 = 0.625 |
| 4 |
5 |
5 |
1 |
(5 - 1)/5 = 0.800 |
0.625 × 0.800 = 0.500 |
| 5 |
6+ |
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| 7 |
9 |
3 |
1 |
(3 - 1)/3 = 0.667 |
0.500 × 0.667 = 0.333 |
| 8 |
9+ |
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| 11 |
22 |
1 |
1 |
(1 - 1)/1 = 0.00 |
0.333 × 0.00 = 0.000 |
Bewick et al. Critical Care 2004 8:389 doi:10.1186/cc2955 |
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