This hypothetical set of data illustrates
how percentages (or their equivalent) can be used to set up a
life table. Both dynamic and time-specific analyses are possible,
but only the former is carried out here. Mortality rates are
given as percent per annum, age intervals as years (Hickey 1952).
| I
Original Data |
Year Banded | Number Banded | Year Reported Dead | Total Dead | |||
| - | - | 1940-41 | 1941-42 | 1942-43 | 1943-44 | - | |
| 1940 | 1000 | 100 | 30 | 10 | 3 | 143 | |
| 1941 | 1000 | - | 95 | 25 | 11 | 131 | |
| 1942 | 1000 |
- | - | 100 | 20 | 120 | |
| Total | 3000 | 100 | 125 | 135 | 34 | 394 | |
| . | |||||||
| II
Same Data on Age-Interval Breakdown |
Year Banded | Number Banded | Number Reported Dead by Age Intervals | Total Dead | |||
| - | - | 0-1 | 1-2 | 2-3 | 3-4 | - | |
| 1940 | 1000 | 100 | 30 | 10 | 3 | 143 | |
| 1941 | 1000 | 95 | 25 | 11 | - | 131 | |
| 1942 | 1000 | 100 | 20 | - | - | 120 | |
| (dx ) Total | 3000 | 295 | 75 | 21 | 3 | 394 | |
| (a) Number of banded birds available per interval | - | 3000 | 3000 | 2000 | 1000 | - | |
| . | |||||||
| III
Life Tablea |
(d x) % Reported dead | 9.83 | 2.5 | 1.05 | .30 | 13.68 | |
| (1 x) % Alive at start | 13.68 | 3.85 | 1.35 | .30 | 19.18 | ||
| (q x) Mortality rate | 72 | 65 | 78 | 100 | 71 | ||
| (d x) No. dead per 1000 banded birds available | 98.3 | 25.0 | 10.5 | 3 | 136.8 | ||
| (1 x) No. alive at start per 1000 available | 136.8 | 38.5 | 13.5 | 3 | 191.8 | ||
| (q x) Mortality rate | 72 | 65 | 78 | 100 | 71 | ||
a d x = dx + a. This technique was independently worked not only in the present study but also by Edward G. Wellein (unpubl. ms.), by Bellrose and Chase (1950), and by Paludin (1951).
Return to Lecture Notes IV. Estimation
of Population Parameters - II. 
Updated 02 August 1996