It's just a simple for loop to sum the variable.
theSum = 0;
for k = 1 : length(x)
theSum = theSum + x(k);
end
theMean = theSum / length(x);
For the SD, it's very very similar - try it yourself this time. If you need to learn MATLAB, check this out: http://www.mathworks.com/matlabcentral/answers/8026-best-way-s-to-master-matlab
