91Ó°ÊÓ

The cohort or generation life table provides information about mortality experience.This life table follows the fate of a cohort with a particular proportion and keeps track of offspring produced by females.

It is known that thetotal number of female offspring produced for a particular age cohort is the number of females alive at the start of the year multiplied by the total number of female offspring produced for each age cohort.

For 0-1 year of age,

Number of females alive at the start of the year=337

The average number of female offspring produced per female=0

The total number of female offspring produced for the 0-1 age cohort\(({T_{0 - 1}})\) is

\(\begin{array}{c}{T_{0 - 1}} = 337 \times 0\\ = 0\end{array}\)

For 1-2 years of age,

Number of females alive at the start of the year=252

The average number of female offspring produced per female=1.07

The total number of female offspring produced for the 0-1 age cohort\(({T_{1 - 2}})\) is

\(\begin{array}{c}{T_{1 - 2}} = 252 \times 1.07\\ = 269.6\\ \simeq 270\end{array}\)

For 2-3 years of age,

Number of females alive at the start of the year=127

The average number of female offspring produced per female=1.87

The total number of female offspring produced for the 0-1 age cohort\(({T_{2 - 3}})\) is

\(\begin{array}{c}{T_{2 - 3}} = 127 \times 1.87\\ = 237.49\\ \simeq 237\end{array}\)

For 3-4 years of age,

Number of females alive at the start of the year=67

The average number of female offspring produced per female=2.21

The total number of female offspring produced for the 0-1 age cohort\(({T_{3 - 4}})\) is

\(\begin{array}{c}{T_{3 - 4}} = 67 \times 2.21\\ = 148.07\\ \simeq 148\end{array}\)

For 4-5 years of age,

Number of females alive at the start of the year=35

The average number of female offspring produced per female=2.59

The total number of female offspring produced for the 0-1 age cohort\(({T_{4 - 5}})\) is

\(\begin{array}{c}{T_{4 - 5}} = 35 \times 2.59\\ = 90.65\\ \simeq 91\end{array}\)

For 5-6 years of age,

Number of females alive at the start of the year=19

The average number of female offspring produced per female=2.08

The total number of female offspring produced for the 0-1 age cohort\(({T_{5 - 6}})\) is

\(\begin{array}{c}{T_{5 - 6}} = 19 \times 2.08\\ = 39.52\\ \simeq 40\end{array}\)

For 6-7 years of age,

Number of females alive at the start of the year=9

The average number of female offspring produced per female=1.70

The total number of female offspring produced for the 0-1 age cohort\(({T_{6 - 7}})\) is

\(\begin{array}{c}{T_{6 - 7}} = 9 \times 1.70\\ = 15.3\\ \simeq 15\end{array}\)

For 7-8 years of age,

Number of females alive at the start of the year=5

The average number of female offspring produced per female=1.93

The total number of female offspring produced for the 0-1 age cohort\(({T_{7 - 8}})\) is

\(\begin{array}{c}{T_{7 - 8}} = 5 \times 1.93\\ = 9.65\\ \simeq 10\end{array}\)

For 8-9 years of age,

Number of females alive at the start of the year=4

The average number of female offspring produced per female=1.93

The total number of female offspring produced for the 0-1 age cohort\(({T_{8 - 9}})\) is

\(\begin{array}{c}{T_{8 - 9}} = 4 \times 1.93\\ = 7.72\\ \simeq 8\end{array}\)

For 9-10 years of age,

Number of females alive at the start of the year=1

The average number of female offspring produced per female=1.58

The total number of female offspring produced for the 0-1 age cohort\(({T_{9 - 10}})\) is

\(\begin{array}{c}{T_{9 - 10}} = 1 \times 1.58\\ = 1.58\\ \simeq 2\end{array}\)

Here, a bar graph with female age in years on the X-axis (0–1, 1–2, and so on) and the total number of female offspring produced for each age cohort on the y-axis is drawn.

For 1-2 years of age,

Number of females alive at the start of the year=252

The average number of female offspring produced per female=1.07

The total number of female offspring produced for the 0-1 age cohort\(({T_{1 - 2}})\) is

\(\begin{array}{c}{T_{1 - 2}} = 252 \times 1.07\\ = 269.6\\ \simeq 270\end{array}\)

The cohort of female Belding’s ground squirrels that produces the most female young is 1-2 years of age.