Basic probability question

Could some please let me know the matlab command to generate a random sequence of 1 and 2 if the P(1)=0.6 and P(2)=0.4.

If we use the command 'randint(1,10,[1,2])' it generates 1,2 with equal probability.

Expecting a response soon. Thanks in advance

Regards

Answer 1

[Daniel Shub]

x = rand(1, 10);  % Makes x have values between 0 and 1.
y = ones(size(x)); % Start off with all ones
y(x > 0.6) = 2; % Change all the values of y, for which x is greater than 0.6 to 2.

Answer 2

[Oleg Komarov]

% Preallocate 1s

Out = ones(100,1);

% 40% shuld be 2s

num = round(numel(Out)*.4);

% Randomly scatter the 2s among the 1s

Out(randi([1 numel(Out)],num,1)) = repmat(2, num,1);

Answer 3

[Royi Avital]

Uniform distribution is always a good point to start from. Then just divide the range [0 1] to whatever ratio you'd like according to the distribution you're after.

numElements = 100;
uniformDist = rand(numElements, 1);
outputDist = zeros(numElements, 1);
outputDist(uniformDist <= 0.6) = 1;
outputDist(uniformDist > 0.6) = 2;

Answer 4

[lemontree45]

Thank you guys. so helpful

Answer 5

[David Young]

You can make a function that you can use instead of rand, like this:

p1 = 0.6;    % probability of a 1 in the output
rand_special = @(m,n) (rand(m,n) > p1) + 1;

Then you can call the function to get an array of the size you want:

rand_special(1, 10)