Editing Survival analysis (section)

====Life table for the aml data====

A [[life table]] summarizes survival data in terms of the number of events and the proportion surviving at each event time point. The life table for the aml data, created using the R{{nbsp}}software, is shown.

{| class="wikitable mw-collapsible"
|+ Life Table for the aml Data
|-
! time !! n.risk !! n.event !! survival !! std.err !! lower 95% CI !! upper 95% CI
|-
| 5 || 23 || 2 || 0.913 || 0.0588 || 0.8049 || 1
|-
| 8 || 21 || 2 || 0.8261 || 0.079 || 0.6848 || 0.996
|-
| 9 || 19 || 1 || 0.7826 || 0.086 || 0.631 || 0.971
|-
| 12 || 18 || 1 || 0.7391 || 0.0916 || 0.5798 || 0.942
|-
| 13 || 17 || 1 || 0.6957 || 0.0959 || 0.5309 || 0.912
|-
| 18 || 14 || 1 || 0.646 || 0.1011 || 0.4753 || 0.878
|-
| 23 || 13 || 2 || 0.5466 || 0.1073 || 0.3721 || 0.803
|-
| 27 || 11 || 1 || 0.4969 || 0.1084 || 0.324 || 0.762
|-
| 30 || 9 || 1 || 0.4417 || 0.1095 || 0.2717 || 0.718
|-
| 31 || 8 || 1 || 0.3865 || 0.1089 || 0.2225 || 0.671
|-
| 33 || 7 || 1 || 0.3313 || 0.1064 || 0.1765 || 0.622
|-
| 34 || 6 || 1 || 0.2761 || 0.102 || 0.1338 || 0.569
|-
| 43 || 5 || 1 || 0.2208 || 0.0954 || 0.0947 || 0.515
|-
| 45 || 4 || 1 || 0.1656 || 0.086 || 0.0598 || 0.458
|-
| 48 || 2 || 1 || 0.0828 || 0.0727 || 0.0148 || 0.462
|}

The life table summarizes the events and the proportion surviving at each event time point. The columns in the life table have the following interpretation:

*time gives the time points at which events occur.
*n.risk is the number of subjects at risk immediately before the time point, t. Being "at risk" means that the subject has not had an event before time t, and is not censored before or at time t.
*n.event is the number of subjects who have events at time t.
*survival is the proportion surviving, as determined using the Kaplan–Meier product-limit estimate.
*std.err is the standard error of the estimated survival. The standard error of the Kaplan–Meier product-limit estimate it is calculated using Greenwood's formula, and depends on the number at risk (n.risk in the table), the number of deaths (n.event in the table) and the proportion surviving (survival in the table).
*lower 95% CI and upper 95% CI are the lower and upper 95% confidence bounds for the proportion surviving.