This is my code and I attached the data file
load 'USS_w3'
USS_w3_POS = USS_w3(USS_w3>0); MEAN = 2.5*mean(USS_w3_POS);
a = 1; for z=1:length(USS_w3)
      if USS_w3(a) < MEAN
          a = a+1;
      else
          c = a;
          while USS_w3(c) > 0
              c = c+1;
          end
          USS_w3(a:c) = 0;
      end
  enda = 1; for z=1:length(USS_w3)
      if USS_w3(a) < MEAN
          a = a+1;
      else
          c = a;
          while USS_w3(c) > 0
              c = c-1;
          end
          USS_w3(c:a) = 0;
      end
  end
      



