math probability 5?

Question

find each theoretical probability. how?
a child being female for any birth in a family
in a family with 2 childern, both are girls
in a family with 3 childern, all are boys

Answer 1

A problem of this kind typically assumes a .5 (50 %) probability of each child born being either sex specifically. To find the probability of two girls we multiply the probabilities of each instance. .50 probability of first child being a girl times .50 probability of second child being a girl: .50 * .50 = .25 probability of both children born are girls. Second question solved in similar fashion. Three children, three boys: .50 * .50 * .50 = .125 or 12.5 %.

Answer 2

As stated, this is not a simple question of probability.

Notice that one family is all female offspring and the other is all male offspring, so this is a question in genetics about non-genetic sex determination factors such as sperm mobility, fluid acidity, or nutrition (or not, there are families of all girls or all boys in which case the coin tosses are exactly analogous).

If it were about reptiles, it would be easier to answer because the sex of offspring is largely determined by the incubation temperature.

Can't help much at present but try something like http://en.wikipedia.org/wiki/Sex_determination

Answer 3

i'm going to do the 1st one for you...the others are comparable P(rolling a quantity > 2) = P(rolling a three, 4, 5, or 6) = 4/6 = 2/3 P(tossing heads) = a million/2 there P(rolling a quantity > 2) and P(tossing heads) =P(rolling a quantity > 2) * P(tossing heads) = a million/3

Answer 4

Theoretically, we consider each birth as tossing a coin. One outcome is boy, the other is girl. With this analogy, you should be able to solve this easy.

Answer 5

1/2,1/3,1/5 . 1 is for the child being female. Then, the number of children in each group determines the second number.

Answer 6

1/2; 1/4; 1/8.