Answer:
77.47%
Explanation:
We have to use Bayes Theorem in solving this problem.
This theorem's formula is:
P(A | B) =
![(P(A and B))/(P(B))](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ouy3z7s8hd6f3oepui4x7jqg45v2q52zie.png)
Where the " | " means "given that".
For our problem, using bayes theorem, we can write:
P(Student has lice | positive ) =
![(P(StudentHasLice and Positive))/(P(Positive))](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jv01rlvg171zvjg1is4ke5wkgg8rvmap0r.png)
- P(Positive) = 0.1692 + 0.0492 = 0.2184
- P (Student has Lice & Positive ) = 0.1692
So P(Student has lice | Positive ) =
![(0.1692)/(0.2184)=0.7747](https://img.qammunity.org/2020/formulas/mathematics/middle-school/t51zz15l43bc3u3s7que3yv30rvfnx5h1v.png)