%100 caminatas -----------------------------

clear x

p=0.5;
deltax=1;
T=1000;

for part=1:100
    x(1,part)=0;
    for i=2:T
        if (rand < p)
            x(i,part)=x(i-1,part)+deltax;
        else
            x(i,part)=x(i-1,part)-deltax;
        end
    end
end

figure(1)
plot(1:T,x)
xlabel('tiempo');
ylabel('posición');

% Media-------------------------------------------

figure(2)
plot(1:T,mean(x'))
xlabel('n');
ylabel('<x>');

% Varianza ---------------------------------------

figure(3)
plot(1:T,mean(x'.^2)-mean(x').^2)
xlabel('n');
ylabel('<x^2> - <x>^2');