Sometimes probability statements are expressed in terms of odds.The odds in favor of an event A are the following ratio.

P(A)/P(not A) = P(A)/P(Ac)

For instance, if P(A) = 0.60, then P(Ac) = 0.40 and the odds infavor of A are 0.60/ 0.40 = 6/4 = 3/2 , written as 3 to 2 or3:2.

(a) Show that if we are given the odds in favor of event A asn:m, the probability of event A is given by the following. P(A) =n/n + m Hint: Solve the following equation for P(A). n/m = P(A)/1 −P(A)

n(1 − P(A)) = _____ (P(A))

n − nP(A) = ____P(A)

n = ____P(A) + nP(A)

n =_____ P(A)

n/n + m = P(A)

(b) A telemarketing supervisor tells a new worker that the oddsof making a sale on a single call are 6 to 19. What is theprobability of a successful call? (Round your answer to two decimalplaces.)

(c) A sports announcer says that the odds a basketball playerwill make a free throw shot are 3 to 5. What is the probability theplayer will make the shot? (Round your answer to two decimalplaces.)

When do creative people get their best ideas? USAToday did a survey of 966 inventors (who hold U.S. patents)and obtained the following information.

Time of Day When Best IdeasOccur
Time	Number of Inventors
6 A.M.-12 noon 12 noon-6 P.M. 6 P.M.-12 midnight 12 midnight-6 A.M.	292 131 328 215

(a) Assuming that the time interval includes the left limit andall the times up to but not including the right limit, estimate theprobability that an inventor has a best idea during each timeinterval: from 6 A.M. to 12 noon, from 12 noon to 6 P.M., from 6P.M. to 12 midnight, from 12 midnight to 6 A.M. (Enter your answersto 3 decimal places.)

6AM-12PM	12PM-6PM	6PM-12AM	12AM-6AM

John runs a computer software store. Yesterday he counted 123people who walked by the store, 52 of whom came into the store. Ofthe 52, only 23 bought something in the store. (Round your answersto two decimal places.)

(a) Estimate the probability that a person who walks by thestore will enter the store.


(b) Estimate the probability that a person who walks into the storewill buy something.


(c) Estimate the probability that a person who walks by the storewill come in and buy something.


(d) Estimate the probability that a person who comes into the storewill buy nothing.