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Part 1, a few questions

1

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It begins..!

1. Chapter 3, q 3.3 - I tried to work out part (iii) from 1st principles and get an answer slightly off, is this due to rounding?

2. Similarly, q 3.11 - I calculated 0.5p65 as exp(0.5 x 0.004332) and get a slightly different answer to that used of (1-q65)^0.5, rounding again or wrong end of stick?
 
Wrong end of stick, I'm afraid!

Looking at your question 2....The value of mu-65 given in the Tables is the instantaneous force of mortality at age 65. This applies at exact age 65 only - it would take a different value at age 65.5, say. The force of mortality is continuously changing and what is given in the Tables are just snapshots - the values at exact ages.

The method shown in the solution to the question derives the constant force of mortality consistent with the probability of survival over the year, which is given in the Tables. The value of mu calculated in this way is close to that at age 65 as you'd expect (hence your answers are close) but not the same (hence the difference).

I assume that your question 1 really boils down to the same issue (though it's hard to tell from what you've written).

On an aside, you'll find that the values of mu given in the Tables really aren't used that much (if at all) in the type of calculations required for CT5 - it's much more to do with lx, dx, qx etc.
 
Hello Mark,

Thanks for clearing that up!

Sorry q1 wasn't clear but I've managed to solve the problem anyway - it was due to the fact that the table uses rounded dx values.
 
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