已知随机变量X1~N(1,9),X2~.N(1,16),X1与X2独立,求P(X1+X1≥2).
由X1~N(1,9),X2~N(1,16),知 X1+X2~N(2,52) P(X1+X2≥2)=P[(X1+X2-2)/5≥(2-2)/5] =1-P[(X1+X2-2)/5﹤0] =1-Φ(0) =0.5
已知随机变量X1~N(1,9),X2~.N(1,16),X1与X2独立,求P(X1+X1≥2).
由X1~N(1,9),X2~N(1,16),知 X1+X2~N(2,52) P(X1+X2≥2)=P[(X1+X2-2)/5≥(2-2)/5] =1-P[(X1+X2-2)/5﹤0] =1-Φ(0) =0.5