Sampling 100 four-child families to estimate the probability that a four-child family has three girls

Question

Cole Kleinow 2021-2-13

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/744552-sampling-100-four-child-families-to-estimate-the-probability-that-a-four-child-family-has-three-girl

回答： Image Analyst 2021-2-14

So I am able to create the familys and count how many familys have 3 daughters but I cant figure out how I would estimate the probability so that I could make a line plot

S = 2;  % 1=boy 2=girl
R = 1;  % coin fliped once
N = 4; % flip 4 coins at once
T = 100;  % repeat 100 times
Out = randi([1 S],[R N T]);
formatSpec = "%x";
for i = 1:T
    for j = 1:N
       a = num2str(Out(:,j,i),formatSpec);
       fam(i,j) = a;
    end
end
match1 = ('1222'); %row you want
eq1 =  sum(all(bsxfun(@eq,fam,match1),2)); %engine
match2 = ('2122'); %row you want
eq2 =  sum(all(bsxfun(@eq,fam,match2),2)); %engine
match3 = ('2212'); %row you want
eq3 =  sum(all(bsxfun(@eq,fam,match3),2)); %engine
match4 = ('2221'); %row you want
eq4 =  sum(all(bsxfun(@eq,fam,match4),2)); %engine
f = [eq1 eq2 eq3 eq4]; 
fd = sum(f);

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Answer 1

Image Analyst 2021-2-14

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/744552-sampling-100-four-child-families-to-estimate-the-probability-that-a-four-child-family-has-three-girl#answer_623212

在 MATLAB Online 中打开

Scrap almost all that and do this:

S = 1;  % 0=boy 1=girl
R = 1000000;  % a million families with 4 children
N = 4; % flip 4 coins at once
Out = randi([0, S], [R, N]);
numGirls = sum(Out, 2);
fd = mean(numGirls == 3) / N

fd =

0.06245675