Question

已知随机变量X～N(1,4),Y=aX+b,N(0,1),则a,b=?

Answer 1

E(ax+b)=a*E(x)+b=2a+b=0; D(ax+b)=a^2*D(x)=4a^2=1; 故a=1/2,b=-1或 a=-1/2,b=1 上面E()表示均值,D()表示方差..