P(Pos) = 0.01
P(Neg) = 0.99
P( Correct | Pos) =0.88
P(Incorrect | Pos) = 0.12
P( Correct |~Pos) = P(Correct | Neg) = 0.85
P( Incorrect |~Pos) = P(Incorrect | Neg) = 0.15
P(Incorrect) = P(Incorrect | Pos)* P(Pos) + P(Incorrect | Neg)*P(Neg)
P(Incorrect) = 0.12*0.01 + 0.15*0.99 = 0.1497