设随机变量<img src="/lqwvjeImg/ff/ff6cc3fc3abbe181015201c03633b611.png">和<img src="/lqwvjeImg/41/414fc87bb5e9067e911af2e4fefd8105.png">都服从标准正态分布,则( )<br>·<img src="/lqwvjeImg/bb/bb33bec1b364b4760e1215f72b0f4ef7.png">服从正态分布<br>·<img src="/lqwvjeImg/fe/fe9b2d79bfebdec2c03d9d015fd64c1d.png">服从<img src="/lqwvjeImg/6b/6b0c3da2f32c735e993e829990e61041.png">布<br>·<img src="/lqwvjeImg/4a/4a97fe1f8d676f40101a379500518b64.png">都服从<img src="/lqwvjeImg/6b/6b0c3da2f32c735e993e829990e61041.png">分布<br>·<img src="/lqwvjeImg/d9/d95075f3751ea0ce03a56cb5e6d1372c.png">都服从<img src="/lqwvjeImg/04/0471da82ea7fa3316648d0e2cedd7b29.png">分布