或用估计量(2) ∑(x1-x) 514 (1342+1162+862+10.42+362) =127.30= − − =  n i xi x 1 2 2 ( ) 5 1 1 ˆ (2)  或用估计量 (13.4 11.6 8.6 10.4 3.6 ) 4 1 2 2 2 2 2 = + + + + = 127.30