x(t+1)=x(t)-1; probability p=0.3
x(t+1)=x(t)-2; probability q=0.2
x(t+1)=x(t)+1; probability p=0.5

p=0.3;
q=0.2;
s=0.5;
numberOfSteps = 100;
maxCount = 10000;
for count=1:maxCount
    x=0;
    for i = 1:numberOfSteps
        random = rand(1, 1);
        if random <=p
            x=x-1;
        elseif random<=(p+q)
            x=x-2;
        else
            x=x+1;
        end
    end
    xfinal(count) = x;
end
[f,x]=hist(xfinal,30);
figure(1)
bar(x,f/sum(f));
xlabel('xfinal')
ylabel('frequency')
mean = mean(xfinal)
variance = var(xfinal)

[nelements,centers] = hist(data,nbins);
  plot(centers,nelements);