function [ stat ] = stat_window(signal, win_size)
    n = length(signal);
    stat = zeros(n, 1);
    for i = 1: n
        for j = 1: win_size
            if i + j - 1 <= n
                stat(i, 1) = stat(i, 1) + signal(i + j - 1, 1);
            end
        end
    end
end