Question

An employee is up for their annual review. The employee believes that there is a 25% chance that they will receive a promotion. Furthermore, if the employee gets promotion there is an 85 % chance they will also receive a raise. However, if the employee does not get promotion there is still a 20% chance that they will receive a raise.

a) What is the probability that the employee will receive a raise?

b) If the employee does NOT receive a raise, what is the probability that the employee will not receive a promotion?

Answer 1

a) P(raise) = P(promotion) * P(raise| promotion) + P(no promotion) *P(raise| no promotion) + =                                    0.25*0.85+0.75*0.2=               0.3625  

b) P(no raise) = 1 - 0.3625 = 0.6375

P(no promotion| no raise) = P(no promotion)*P(no raise| no promotion)/P(no raise)=               0.75*(1-0.2)/0.6375=  0.9412