For each birth, you have two choices - either a boy or a girl. Then, the probability for a certain birth to obtain a choice is ½.
Using Binomial Theorem, we have (10 choose 8)(½)8(½)² = 45/1024.
0.48
This is a Binomial Probability; p=0.5, n=10 & x=7. Since you want the probability of exactly 7, in the related link calculator, after placing in the above values, P(x=7) = 0.1172 or 11.72%.
6 out of 9.
50/50
3/8
25
0.48
This is a Binomial Probability; p=0.5, n=10 & x=7. Since you want the probability of exactly 7, in the related link calculator, after placing in the above values, P(x=7) = 0.1172 or 11.72%.
In a family with four children, the probability of having four boys is 1 in 16.
6 out of 9.
1/8
50/50
3/8
These events are independent; so the probability of a girl is 0.5.
Assuming that having boys and girls are equally likely, then the probability is 1/8. * * * * * You also need to assume that the children's genders are independent. They are NOT and depend on the parents' ages and genes.
1/4
Since the probability of having a son is about 1/2, the probability of the first 4 children being boys is about (1/2)4.