SOLUTION: Suppose the proportion of female students at your school is 55%. Also you know that 20% of the male students smoke and only 5% of the female students smoke. Suppose you randomly

Algebra ->  Probability-and-statistics -> SOLUTION: Suppose the proportion of female students at your school is 55%. Also you know that 20% of the male students smoke and only 5% of the female students smoke. Suppose you randomly      Log On


   

Question 1179027: Suppose the proportion of female students at your school is
55%. Also you know that 20% of the male students smoke
and only 5% of the female students smoke. Suppose you
randomly select a student.
(a) Find the probability the student is a male smoker.
(b) Find the probability the student smokes.
(c) If the student smokes, what is the probability the
student is female?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi
Females: .55(.05 smoke)  and Males: .45 (.20smoke)
(a) Find the probability the student is a male smoker: P = (.45)(.20)
(b) Find the probability the student smokes.
 P = (.45)(.20) + (.55)(.05) = .1175
(c) If the student smokes, what is the probability the student is female?
   P(A|B) = P(A and B)/P(B)
     P(female|smoker) = (.55)(.05)/ .1175 = .0275/.1175 = .234

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