Computing the mean over 3 numbers in a vector

Hi

I have a vector that I want to find the average over each 3 numbers. So if I have a vector A and sampling it over 3 I would get new_A. However my solution isn't working. Could you help me?

A = [1 2 3 4 5 6 7 8 9 10 11 12 13 14 15]; %The vector

count = 1;
for i = 1:3:length(A)
    new_A(count) = mean(A(i:i+1));
    count = count+1;
end

new_A = [2 5 8 11 14]; %The desired ouput

Answer 1

[Rick Rosson]

... = mean(A(i:i+2));

Answer 2

[Walter Roberson]

Sliding window or each distinct group of 3? If it is each distinct group of 3, then reshaping to 3 x something and then mean() along the dimension you made 3.