"Combined" group in survival

jswislar

There's a "combined" group in my survival output. This is the survival time with all groups combined. OK, but how is it that the survival time for this group exceeds the survival for any of my individual groups? Shouldn't it be more of an average?

 

Here are my results.

Group   # Failed    # Censored    Mean    

1            182            1981            1360.99

2            820            9736            1285.93

3            254            4072            1263.10

4            49              616              1168.80

Cmbnd  1305          16405          1369.43

Ted

The "combined" group mean time before the event is not equal to the mean of other means. Do not bother In any case, because it makes little sense to interpret the survival of a combined group.