What do you want to do for elements 1-49? Or the final 49 elements? Do you want the window to shrink as your window would leave the array? Do you just want those places where the window fits complete in your array? Did you just try a simple for loop:
ratData = rand(1, 500); % Sample data
windowWidth = 50;
averagedData = zeros(1, length(ratData) - windowWidth);
for k = 1 : length(ratData) - windowWidth
averagedData(k) = mean(ratData(k:k+windowWidth-1));
end
plot(ratData, 'b-', 'LineWidth', 2);
hold on;
plot(averagedData, 'r-', 'LineWidth', 2);
grid on;
legend('Actual', 'Averaged');
msgbox('Done!');
