Calculating Posterior Probability with two variables

Hey Guys,

Could anyone please help me out with this question?

**Calculate the posterior probability of patient having flu given cough positive and fever negative?**

Sensitivity of cough for flu: 60%

Sensitivity of fever for flu: 70%

Specificity of fever for flu: 80%

Specificity of cough for flu: 50%

Prior of flu: 10%

Greatly appreciated!(Happy)

Rico

Re: Calculating Posterior Probability with two variables

Quote:

Originally Posted by

**rico** **Calculate the posterior probability of patient having flu given cough positive and fever negative?**

Sensitivity of cough for flu: 60%

Sensitivity of fever for flu: 70%

Specificity of fever for flu: 80%

Specificity of cough for flu: 50%

Prior of flu: 10%

Greatly appreciated!(Happy)Rico

$\displaystyle P({flu})=.10$

$\displaystyle P({cough}|{no$\_$fever})=\frac{.60+.80}{.60+.70+.8 0+.50}=.53846$

$\displaystyle P({cough}|{flu})=p({flu})*P({cough}|{no\_fever})=. 053846$

double check this!

Re: Calculating Posterior Probability with two variables