设该组数据的方差为D(X),平均数为E(X)=（x1+x2+x3+````+`xn）/n,
则D(X)=求和i=1到n,(Xi-E(x))^2..
则新一组数据有2x1,2x2,2x3```2xn,则E1(X)=（2x1+2x2+2x3+````+2xn）/n=2E(X)
则D1(X)=求和i=1到n,(2Xi-2E(x))^2=2^2D(X)=8.
详细过程,给分吧!