Approximately one-third of all human twins are identical (one-egg) and two thirds are fraternal (two-egg) twins. Identical twins are necessarily the same sex, with female and male being equally...

Approximately one-third of all human twins are identical (one-egg) and two thirds are fraternal (two-egg) twins. Identical twins are necessarily the same sex, with female and male being equally likely. Among fraternal twins, approximately one-fourth are both female, one-fourth are both male, and half are one female and one male. Finally, among all births in the United States, approximately 15 in 1000 are twin births.

A= {a U.S. birth results in twin females}

B = {a U.S. birth results in identical twins}

C = {a U.S. birth results in twins}

1. Is P(A∩B∩C) equal to P(A)P(B)P(C)?


2. Find P(A ∩ B) and P(A∩C).


3. Compare P(A ∩ C) with P(A)P(C)


4. Which event is pairwise independent?