A total of 46 percent of the voters in a certain city classify themselves as Indepen-dents, whereas 30 percent classify themselves as Liberals and 24 percent say thatthey are Conservatives. In a recent local election, 35 percent of the Independents,62 percent of the Liberals, and 58 percent of the Conservatives voted. A voter ischosen at random. Given that this person voted in the local election what is theprobability that he or she is

A total of 46 percent of the voters in a certain city classify themselves as Indepen-dents, whereas 30 percent classify themselves as Liberals and 24 percent say thatthey are Conservatives. In a recent local election, 35 percent of the Independents,62 percent of the Liberals, and 58 percent of the Conservatives voted. A voter ischosen at random. Given that this person voted in the local election what is theprobability that he or she is Given that this person voted in the local election, what is the probability that he or she is (a) an Independent? (b) a Liberal? (c) a Conservative? (d) What fraction of voters participated in the local election?

Answer:

A) 0.331 ; B) 0.383 ; C) 0.286 ; D) 0.4862

Step-by-step explanation:

Given the following :

P(Independent(I)) = 46/100 = 0.46

P(Liberal(L)) = 30/ 100 = 0.3

P(Conservative(C)) = 24 / 100 = 0.24

Election participation (EP) :

P(EP | I) = 35 / 100 = 0.35

P(EP | L) = 62/100 = 0.62

P(EP | C) = 58/100 = 0.58

P(EP) = P(EP | L)*P(L) + P(EP | I)*P(I) + P(EP | C)*P(C)

P(EP) = (0.62*0.3) + (0.35*0.46) + (0.58*0.24)

P(EP) = 0.186 + 0.161 + 0.1392 = 0.4862

A) probability of Independent given that the person participated in election:

P(I Given EP) = [P(EP | I) * P(I)] / P(EP)

= (0.35 * 0.46) / 0.4862

= 0.161 / 0.4862

= 0.331

B) probability of Liberals given that the person participated in election:

P(L Given EP) = [P(EP | L) * P(L)] / P(EP)

= (0.62 * 0.3) / 0.4862

= 0.186 / 0.4862

= 0.383

C.) P(C Given EP) = [P(EP | C) * P(C)] / P(EP)

= (0.58 * 0.24) / 0.4862

= 0.1392 / 0.4862

= 0.286