axMidpoint approximates a(x) using interval midpoints

Description

approximates a(x) using interval midpoints (except a0, which is estimated using a rule-of-thumb formula scaled by m0)

Usage

1
axMidpoint(Mx, n)

Arguments

Mx

a numeric vector of central death rates, defined as deaths/exposure.

n

a numeric vector of the age-interval widths. Must be the same length as Mx.

Details

All values will be in the exact middle of the age interval, except for a0, which uses: a0 = .07 + 1.7 * M0.

Value

returns a numeric vector of ax values

Author(s)

Tim Riffe

References

formula for a0 as suggested by: Keyfitz, N. (1970), Finding probabilities from observed rates, or how to make a life table. The American Statistician (1970), pp. 28-33

See Also

See Also axEstimate, a wrapper function for this and 3 other a(x) estimation methods (axKeyfitz,axSchoen and axPreston).

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