送交者: mangolasi 于 2006-2-02, 16:57:09:
回答: lost life expectation is .012*(\sum_{i=1}{n} (1-survival rate)^i 由 mangolasi 于 2006-2-02, 16:44:23:
lost of surviving chance=.012*(1-survial_60)*(1+survival_60+survival60*survival_61+...)
meaning lost the .012 to survive to 60 and die at 60 (1 year more), .012*survival_60 chance to survive to 61 and die at 61 (another year more), and so on.
Constant survial rate of .7 (so the % guys survive to 70 is .028--almost dying out).
The lost of life expectency is:
.3*.012*((1-.7^10)/(1-.7))
[1] 0.01166103
Bad habit of forgetting formulas immediately after exam.