However, since we are dealing with time series data, there is a possibility of Autocorrelation (that is E (uiuj) =/=0 i=/=j)).
ຢ່າງໃດກໍຕາມ, ນັບຕັ້ງແຕ່ພວກເຮົາກໍາລັງ dealing ມີຂໍ້ມູນໄລຍະທີ່ໃຊ້ເວລາ, ມີຄວາມເປັນໄປໄດ້ຂອງ Autocorrelation (ທີ່ E (uiuj) = / = 0 i = / = j)).