We have been given that the lifespans of lions in a particular zoo are normally distributed. The average lion lives 12.5 years; the standard deviation is 2.4 years. We are asked to find the probability of a lion living longer than 10.1 years using empirical rule.
First of all, we will find the z-score corresponding to sample score 10.1.
, where,
z = z-score,
x = Random sample score,
= Mean
= Standard deviation.
![z=(10.1-12.5)/(2.4)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/9f3p552espsxnb3wxi11ocddomfx892du8.png)
![z=(-2.4)/(2.4)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/jkikaubinzjo5n5v6jl1vrualrm47cuy76.png)
![z=-1](https://img.qammunity.org/2021/formulas/mathematics/high-school/qw8fgt0ju3v631wzypnyjrnsa66aphjw8r.png)
Since z-score of 10.1 is
. Now we need to find area under curve that is below one standard deviation from mean.
We know that approximately 68% of data points lie between one standard deviation from mean.
We also know that 50% of data points are above mean and 50% of data points are below mean.
To find the probability of a data point with z-score
, we will subtract half of 68% from 50%.
![(68\%)/(2)=34\%](https://img.qammunity.org/2021/formulas/mathematics/middle-school/9xtfogke9a8jxjf4v4n2e8ne85v6jyugam.png)
![50\%-34\%=16\%](https://img.qammunity.org/2021/formulas/mathematics/middle-school/5wil9uwr52wuabmtjw4m0ns24zz7vzriid.png)
Therefore, the probability of a lion living longer than 10.1 years is approximately 16%.