Question

设随机变量是X~N（2,4）,若ax+b~N(0,1),则求a,b各是几? 求解,谢谢

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.