It is difficult to answer this question properly.
One reason is that children's genders are not independent of one another: the gender depends on the parents' genetics and their age.
The second reason is that the probability of a girl is not 0.50 but approx 0.48.
However, if you ignore reality, then the answer is (1/2)4 = 1/16
The probably of four girls in a family with four children is 1/16. I got this answer because: Probability of a girl is 1/2 and to get all girls you would multiply it by 1/2 for the rest of the girls.
The probability of a boy is still 0.5 no matter how many prior children there are.
In a family with four children, the probability of having four boys is 1 in 16.
3 out of 7
1 in 2
There is no simple answer to the question because the children's genders are not independent events. They depend on the parents' ages and their genes. However, if you assume that they are independent events then, given that the probability of a boy is approx 0.52 in all cases, the overall probability is 0.0624.
2/4
There is no simple answer to the question because the children's genders are not independent events. They depend on the parents' ages and their genes. However, if you assume that they are independent events then, given that the probability of a girl is approx 0.48, the probability of 2 or more girls is 0.6617.
50-50
In a world in which every family has seven children (quite unlikely!) the probability would be 35/128 = 0.273. However in the world that we live in, families with 7 children are very rare and so the answer would be 0.273 of that very rare proportion.
There is no simple answer to the question because the children's genders are not independent events. They depend on the parents' ages and their genes. However, if you assume that they are independent events then, given that the probability of a boy is approx 0.52, the probability of the other two being boys is 0.2672.
Yes Ambrose Burnside had a family he had a wife named Sarah and five children, four girls and one boy. You're Welcome ;)