CLT

SN = [];
n = 1000000;
m = 1000;

for i = 1:n
    aR = [];
    for j = 1:m
        x = rand;
        if x < 0.5
            aR(j) = 1;
        elseif x < 0.7
            aR(j) = 2;
        elseif x < 0.9
            aR(j) = 3;
        else
            aR(j) = 4;
        end
    end
    SN(i) = sum(aR)/sqrt(m);
end

A = (var(SN));

figure(1)
histogram(SN, 'Normalization', 'pdf')
figure(2)
histogram(SN, 'Normalization', 'cdf')