Choose random between two option.
显示 更早的评论
Hi, i want to choose randomly between the "boy" or "girl", how can i do that? Each has the same probability of 50%.
i want to calculate this question:
In a country in which people only want boys … … every family continues to have children until they have a boy. If they have a girl, they have another child. If they have a boy, they stop. What is the proportion of boys to girls in the country? Tnx
回答（2 个）
Image Analyst
2017-3-23
Hint:
sexes = {'Boy', 'Girl'};
r = randi([1, 2], 1) % Get a 1 or 2 randomly.
thisSex = sexes(r) % Extract the sex for this random number.
3 个评论
Valerie Reinisch
2020-12-22
Hi, what is the solution if the probability for the boy is 60% and for girl 40%?
Walter Roberson
2020-12-22
编辑：Walter Roberson
2020-12-22
r = rand() > 0.60
thisSex = sexes{r+1}
By the way: my modeling says 2/3 girls on average.
Valerie Reinisch
2020-12-22
Tried it in the meanwhile with this:
r = binornd(1,0.6)
But thanks a lot for this quick answer! (:
Roger Stafford
2017-3-23
编辑：Roger Stafford
2017-3-23
There should be no need to go through such a simulation. For each birth the probability that a boy is born is one-half regardless of all the tricks the family may play.
However if you are addicted to more complicated computations, the average number of boys per family is:
1/2*1 + 1/4*1 + 1/8*1 + ... = 1
and the average number of girls per family is:
1/2*0 + 1/4*1 + 1/8*2 + 1/16*3 + 1/32*4 + ... = 1
You can use symsum to verify these.
1 个评论
trials = 1E6;
isboy = rand(trials,53) <= 0.5;
child_number_for_boy = sum(cumprod(~isboy,2),2) + 1;
avg_number_of_girls = mean(child_number_for_boy - 1)
max_number_of_girls = max(child_number_for_boy) - 1
类别
在 帮助中心 和 File Exchange 中查找有关 Large Files and Big Data 的更多信息
2020-12-22
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
