Question

Suppose that we have a sample space S5 {E1, E2, E3, E4E4E, E5, E6, E7}, where E1, E2, . . ., E7 denote the sample points. The following probability assignments apply: P(E1) 5 .05, P(E2) 5 .20, P(E3) 5 .20, P(E4) 5 .25, P(E5) 5.15, P(E6) 5 .10, and P(E7) 5 .05. LetA5{E1,E4E4E,E6}B5{E2E2E,E4E4E,E7E7E}C5{E2E2E,E3,E5,E7E7E}a.Find P(A(A(), P(B), and P(C).b.Find AB and P(A(A(>B).d.Are events A and C mutually exclusive?C mutually exclusive?Ce.Find Bc and P(Bc).

Answer 1

P(A) = 0.4 ; P(B) = 0.50 ; P(C) = 0.60 ; P(A u B) = 0.65 ; P(A n B) = 0.25 ;

A and C are mutually exclusive ;

0.5

Explanation:

S = {E1, E2, E3, E4, E5, E6, E7}

P(E1) = .05, P(E2) = .20, P(E3) = .20, P(E4) = .25, P(E5) = .15, P(E6) = .10, and P(E7) = .05

Let:

A{E1,E4,E6}

B{E2,E4,E7}

C{E2,E3,E5,E7}

P(A) = 0.05 + 0.25 + 0.10 = 0.40

P(B) = 0.20 + 0.25 + 0.05 = 0.50

P(C) = 0.20 + 0.20 + 0.15 + 0.05 = 0.60

AUB = {E1, E2, E4, E6, E7}

P(A u B) = 0.05 + 0.20 + 0.25 + 0.10 + 0.05 = 0.65

AnB = {E4}

P(A n B) = 0.25

A and C are mutually exclusive if AnC = ∅

A n C = ∅

Hence, A and C are mutually exclusive.

B complement = B' = {E1, E3, E5, E6}

P(B') = 0.05 + 0.20 + 0.15 + 0.10 = 0.5