2/6 is not accurate. using a theoretical method for equally likely outcomes, there are 2 possible outcomes for each birth: either a boy(B), or a girl (G). For a family of three children, the total number of possibilities (birth orders) is 2*2*2=8 to double check this work, here are the eight possible outcomes:
BBB, BBG, BGG, GBB, GBG, GGB, and GGG. You want EXACTLY two girls, this assumes that the other must be a boy. Therefore, the probability that a three child family has 2 girls one boy is P(2 girls)=3/8=0.375
It is 3/8.
2/4
The probability is 0.4231, approx.
It is approx 78.8%
1 in 13
It is 3/8.
2/4
The probability is 0.4231, approx.
It is approx 78.8%
1 in 13
It is 0.02
0.7881 approx.
1/26
The probability is 7:12... There are five months with less than 31 days, so the probability of selecting a month with exactly 31 days is 7 out of 12.
Empirical
50%
There are infinitely many numbers and so the probability of the second event is 0. As a result the overall probability is 0.