Completion requirements
Work these exercises to see how well you understand this material.
Solutions
-
- {b, c}
- {a}
- ∅
-
- H = {hhh, hht, hth, htt, thh, tht, tth}, M = {hhh, hht, hth, thh}
- H ∩ M = {hhh, hht, hth, thh}, H ∪ M = H, Hc = {ttt}
- P(H ∩ M) = 4/8 , P(H ∪ M) = 7∕8, P(Hc)=1∕8
- Mutually exclusive because they have no elements in common.
-
- B = {b1, b2, b3, b4}, R = {r1,r2,r3,r4}, N = {b1,b2,y1,y2,g1,g2,r1,r2}
- B ∩ R = ∅, B ∪ R = {b1, b2, b3, b4, r1, r2, r3, r4}, B ∩ N = {b1, b2}, R ∪ N = {b1, b2, y1, y2, g1, g2, r1 ,r2, r3, r4}, Bc = {y1, y2, y3, y4, g1, g2, g3, g4, r1, r2, r3, r4}, (B ∪ R)c = {y1, y2, y3, y4, g1, g2, g3, g4}
- P(B ∩ R) = 0, P(B ∪ R) = 8∕16, P(B ∩ N) = 2∕16, P( R ∪ N) = 10∕16, P(Bc) = 12∕16, P((B ∪ R)c) = 8/16
- Not mutually exclusive because they have an element in common.
-
- 0.36
- 0.78
- 0.64
- 0.27
- 0.87
-
- P(A) = 0.38, P(B) = 0.62, P(A ∩ B) = 0
- P(U) = 0.37, P(W) = 0.33, P(U ∩ W) = 0
- 0.7
- 0.7
- A and U are not mutually exclusive because P(A ∩ U) is the nonzero number 0.15. A and V are mutually exclusive because P(A ∩ V) = 0.
-
- "four or less"
- "an odd number"
- "no heads" or "all tails"
- "a freshman"
-
- "All the children are boys".
Event: {bbg, bgb, bgg, gbb, gbg, ggb, ggg},
Complement: {bbb} - "At least two of the children are girls" or "There are two or three girls".
Event: {bbb, bbg, bgb, gbb},
Complement: {bgg, gbg, ggb, ggg} - "At least one child is a boy".
Event: {ggg},
Complement: {bbb, bbg, bgb, bgg, gbb, gbg, ggb} - "There are either no girls, exactly one girl, or three girls".
Event: {bgg, gbg, ggb},
Complement: {bbb, bbg, bgb, gbb, ggg} - "The firstborn is a boy".
Event: {gbb, gbg, ggb, ggg},
Complement: {bbb, bbg, bgb, bgg}
- "All the children are boys".
- 0.47
-
- 0.0023
- 0.9977
- 0.0009
- 0.3014
-
- 920/1671
- 668/1671
- 368/1671
- 1220/1671
- 1003/1671
-
- {hhh}
- {hht, hth, htt, thh, tht, tth, ttt}
- {ttt}