Given:
P(H)=0.25,P(+)=0.20,P(+β£Hβ²)=0.05.
Find sensitivity from total probability:
0.20=P(+β£H)β
0.25+0.05β
0.75βΉP(+β£H)=0.65.
So P(ββ£H)=0.35,P(ββ£Hβ²)=0.95.
Compute P(β):
P(β)=0.35β
0.25+0.95β
0.75=0.80.
Apply Bayes for P(Hβ²β£β):
P(Hβ²β£β)=P(β)P(ββ£Hβ²)P(Hβ²)β=0.800.95β
0.75β=0.800.7125ββ0.890625(89.06%).
Conclusion: the correct posterior β89.1%. None of the given choices match exactly; C (87%) is closest and D (93%) is incorrect.