math

4. b) P (A/Bi)=0 for i<=r since the best candidate is not chosen from any particular group.

P(A/BI)= r/(i-1) for r<I

This is the probability (applicant is selected/applicant is the best)

=Σr-11=1 0+ Σnr p(applicant is selected/applicant is the best)

Σnr r/(i-1) But i>r so P(A/BI)= r/(i-1)

c. 1) if r=1 best candidate selected is 1/n

2) 0<r<n

Pr= Σnr+1 p(Applicant is selected Ω applicant is the best)

= Σnr+1 p(Applicant is selected Ω applicant is the best)