(x1+x2+……+xn）/n=9
(x1+2+x2+2+……+xn+2）/n
=[(x1+x2+……+xn）+2n]/2
=(9n+2n)/n
=11
设最大数为xa,最小数为xb
则另一样本最大数为xa,最小数为xb
(xa+2)-(xb+2)=xa+2-xb-2
=xa-xb
=2