question 16

A certain virus infects one in every 150 people. A test used to detect the virus in a person is positive 80% of the time when the person has the virus and 15% of the time when the person does not have the virus.(This 15% result is called a false positive.) Let A be the event"the person isinfected" and B be the event"the person testspositive."

(a) UsingBayes' Theorem, when a person testspositive, determine the probability that the person is infected.

(b) UsingBayes' Theorem, when a person testsnegative, determine the probability that the person is not infected.

(a) The probability that a person is infected when a person tests positive is

(Do not round until final answer. Then round to three decimal places asneeded.)

(b) The probability that a person is not infected when a person tests negative is

(Round to four decimal places asneeded.)

question 2

Given thatP(A or B)=1/5, P(A)=1/7, andP(A and B)=1/8, findP(B).

A.

131/280

B.

61/280

C.

1/14

D.

51/280

question 20

The table lists the smoking habits of a group of college students.

SexNon-smokerRegularSmokerHeavySmokerTotalMan135705210Woman187218216Total3229113426

If a student is chosen atrandom, find the probability of getting someone who is a man or anon-smoker. Round your answer to three decimal places.

A.

0.932

B.

0.786

C.

0.950

D.

0.941