IAI Actuarial Core Principles · Risk Modelling and Survival Analysis · Transition intensities dependent on age (exact or census)
A study of 200 policyholders in an Indian insurer records 8 deaths over a total of 1,600 life-years of observation. Assuming a constant force of mortality, the maximum likelihood estimate of mu and the estimated variance of the estimator (approximately d/V^2) are respectively:
The estimate is 8/1600 = 0.005, and the approximate variance is d/V^2 = 8/1,600^2 ≈ 0.0000031. Dividing deaths by lives instead of by waiting time would wrongly give 0.04.
- A0.005 and 0.0000250
- B0.040 and 0.0000250
- C0.005 and 0.0000031Correct
- D0.005 and 0.0050000
- 0.040 and 0.0000031
Explanation
MLE = d/V = 8/1600 = 0.005. Variance ≈ d/V^2 = 8/2,560,000 = 0.000003125, about 0.0000031. The option with 0.0000250 uses d^2/V... mistakes such as 8/200=0.04 use number of lives instead of exposure.
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