2006-07-21 22:21:41 · 7 answers · asked by dao n 1 in Science & Mathematics ➔ Mathematics
dao,
(Please be as clear as you can, and award 10 points appropriately. Don't let your questions go to a vote.)
Since probability of boy = prob of girl = 0.5, we have the following:
Prob 0 boys = (0.5)^10 = 0.0009766 = P
Prob 1 boy = 10 P
Prob 2 boys = 10C2 P = 45 P
Prob 3 boys = 10C3 P = 120 P
Prob 4 boys = 10C4 P = 210 P
Prob of less boys than girls =
(1+10+45+120+210) x P = 386 P = 0.376953..
Alternately, you can compute the probability of there being 5 girls (G) and 5 boys (B):
A couple of the ways this could happen are:
GGGGGBBBBB or GBGBGBGBGB
These events both have probability P= 0.0009766
How many ways are there? This is given by the binomial coefficient !0C5 = 252. So the prob that there will be an equal number of boys and girls = 252 P = 0.24609..
Because prob girl = prob boy = 0.5, this distribution is symmetric and the prob of less boys than girls ( or less girls than boys) is simply (1-0.24609)/2 = 0.37953... And of course, this is the same as above>
2006-07-21 22:49:01 · answer #1 · answered by Jimbo 5 · 0⤊ 0⤋
first write down all the possible outcomes.
1 boy and 9 girls= 10%
2 boys and 8 girls = 10%
3 boys and 7 girls = 10%
4 boys and 6 girls = 10%
5 boys and 5 girls = 10%
6 boys and 4 girls = 10%
7 boys and 3 girls = 10%
8 boys and 2 girls = 10%
9 boys and 1 girl = 10%
10 boys and 0 girls = 10%
10 girls and 0 boys = 10%
But in genetics the chromosomes for a girl is xx but for a boy is xy. So the ratio of 3:1 so that's why there are more girls in the world than boys
2006-07-21 23:54:00 · answer #2 · answered by Ultimate Chopin Fan 4 · 0⤊ 0⤋
the probability for boys being more than girls include, 6 boys 4 girls, 7 boys 3 girls, 8 boys 2 girls, 9 boys 1 girl
6 boys + 4 girls probability =7 boys+3 girls=8boys +2 girls+9 boys +1girl=0.5 to the power of 10=0.0009765625
the final proababilty is the addition of the the probabilty of these 4 possiblities=0.0009765625 * 4=0.00390625
2006-07-21 22:31:30 · answer #3 · answered by The Hitman 4 · 0⤊ 0⤋
the question is not structured properly. you need the actual number for probability of boy : girl
2006-07-21 22:27:01 · answer #4 · answered by no-one listens... 2 · 0⤊ 0⤋
stop posting this question over and over again it can get you kicked off yahoo by the way
2006-07-21 22:25:47 · answer #5 · answered by flamebabe9 4 · 0⤊ 0⤋
is this family have no care family planing.
2006-07-21 22:43:07 · answer #6 · answered by uncle podger 3 · 0⤊ 0⤋
ask theirparent why you getting tension
2006-07-21 22:51:08 · answer #7 · answered by truth speaker 2 · 0⤊ 0⤋