# How do I construct a demographic life table? (Yes, homework help.)

Asked by dpworkin (27035) March 1st, 2010

Does anyone know the formulae to derive l of x, nd of x, nL of x, T of x and e of x? (sub1 L sub 0=.31 sub0+.71 sub 1.)

Observing members: 0 Composing members: 0

Do you mean ”e of x” like the function e(x), or are you talking about exponents, such as e^x?

jfos (7362)

These are specific variables for life tables where x is age at entry (e.g. 1.00 for age 0) q of x is expected mortality per cohort, d of x is actual death per cohort, etc.

There are formulae to derive each subsequent statistic beginning with the radex, but I don’t know what they are.

dpworkin (27035)

Hm, I don’t understand your explanation well enough. I could understand if each different letter represented a different function, such as q(x) = x^2 + 0.38x and d(x) = x^2 + x(1 – e^x) or along those lines. Then the derivative could be found by more or less basic methods.

jfos (7362)

These equations are specific to demographics. I don’t need help with algebra or arithmetic, I need help with demographic anthropology. I don’t have the equations, and I haven’t been able to find them on line except for species other than Homo.

dpworkin (27035)

Hm, well if in your orginal question you meant “derive” as to calculate the derivative, then it doesn’t matter what the equations represent. I’m thinking that you must have meant “derive” in more of a “synthesize” kind of way, in which case, I can’t help.

jfos (7362)

right. i’m no mathematician.

dpworkin (27035)

Good luck.

jfos (7362)

Sorry dp… I don’t have my epidemiology notebook handy (and even if I did I don’t think I could explain it well in this little box)... but here are a few links that you have probably already looked at:

1, 2, 3, 4.

Good luck!

Cupcake (13466)

Thanks, @Cupcake. The Life Table Basics page had 3 of the formulae I needed, and I asked my professor about the remaining one – it turned out to be an arbitrary equation designed to curve a function that was too linear in the first year of human life. Homework done, much relief. Ya gotta love Fluther, dontcha?

dpworkin (27035)

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