For 5 years, a biologist studied a population of mice living in a field. The mice have three age classes: 1 year old, 2 years old, and 3 years old. The number of individuals in each age class over the course of the study is shown in the table.
$$\begin{array} { | c | c | c | c | }
\hline \begin{array} { c }
\text { Age in } \
\text { Years } ( \mathrm { x } )
\end{array} & \begin{array} { c }
\text { Survival Rate } \
\left( \mathrm { s } _ { \mathrm { x } } \right)
\end{array} & \begin{array} { c }
\text { Survivorship } \
\left( \mathrm { l } _ { \mathrm { x } } \right)
\end{array} & \begin{array} { c }
\text { Fecundity } \
\left( \mathrm { b } _ { \mathrm { x } } \right)
\end{array} \
\hline 1 & 0.1 & 1.0000 & \
\hline 2 & 0.8 & 0.1000 & \
\hline 3 & 0.8 & 0.0800 & \
\hline 4 & 0.8 & 0.0640 & 10 \
\hline 5 & & 0.0512 & 20 \
\hline
\end{array}$$

Question

For 5 years, a biologist studied a population of mice living in a field. The mice have three age classes: 1 year old, 2 years old, and 3 years old. The number of individuals in each age class over the course of the study is shown in the table. 
$$\begin{array} { | c | c | c | c | } 
\hline \begin{array} { c } 
\text { Age in } \
\text { Years } ( \mathrm { x } )
\end{array} & \begin{array} { c } 
\text { Survival Rate } \
\left( \mathrm { s } _ { \mathrm { x } } \right)
\end{array} & \begin{array} { c } 
\text { Survivorship } \
\left( \mathrm { l } _ { \mathrm { x } } \right)
\end{array} & \begin{array} { c } 
\text { Fecundity } \
\left( \mathrm { b } _ { \mathrm { x } } \right)
\end{array} \
\hline 1 & 0.1 & 1.0000 & \
\hline 2 & 0.8 & 0.1000 & \
\hline 3 & 0.8 & 0.0800 & \
\hline 4 & 0.8 & 0.0640 & 10 \
\hline 5 & & 0.0512 & 20 \
\hline
\end{array}$$

Quizplus · Accepted Answer

The average lifespan (life expectancy) can be calculated using the formula for life expectancy in a life table: $ e_0 = \sum (l_x \cdot b_x) $. Calculating this gives approximately 4.6 years.

For 5 Years, a Biologist Studied a Population of Mice