32.50,29.66.31.05的平均数为31.08
则方差s²=s^2=1/n[(x1-m)^2+(x2-m)^2+.+(xn-m)^2]
=1/9[(32.50-31.08)^2+(29.66-31.08)^2+.+(31.05-31.08)^2]
=1.06