In the following matrix, the weighing factors of different criteria for three pumps are given (cost 0.3: 9, 5, 8; efficiency 0.3: 7, 9, 7; reliability 0.25: 8, 9, 9; maintenance 0.15: 6, 7, 6 for pumps A, B, C). Calculate the weighted average and select the best pump. Is it statistically significant?