随机变量的方差和标准差的疑问设随机变量的分布函数为F(x)=1-e^(-x^2),x>0试求E(x)和Var(x)我的做法是先求出概率密度p(x)=2xe^(-x^2)再求出E(x)为什么不对哪里错了?
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/10 06:48:22
![随机变量的方差和标准差的疑问设随机变量的分布函数为F(x)=1-e^(-x^2),x>0试求E(x)和Var(x)我的做法是先求出概率密度p(x)=2xe^(-x^2)再求出E(x)为什么不对哪里错了?](/uploads/image/z/7567466-50-6.jpg?t=%E9%9A%8F%E6%9C%BA%E5%8F%98%E9%87%8F%E7%9A%84%E6%96%B9%E5%B7%AE%E5%92%8C%E6%A0%87%E5%87%86%E5%B7%AE%E7%9A%84%E7%96%91%E9%97%AE%E8%AE%BE%E9%9A%8F%E6%9C%BA%E5%8F%98%E9%87%8F%E7%9A%84%E5%88%86%E5%B8%83%E5%87%BD%E6%95%B0%E4%B8%BAF%28x%29%3D1-e%5E%28-x%5E2%29%2Cx%3E0%E8%AF%95%E6%B1%82E%28x%29%E5%92%8CVar%28x%29%E6%88%91%E7%9A%84%E5%81%9A%E6%B3%95%E6%98%AF%E5%85%88%E6%B1%82%E5%87%BA%E6%A6%82%E7%8E%87%E5%AF%86%E5%BA%A6p%28x%29%3D2xe%5E%28-x%5E2%29%E5%86%8D%E6%B1%82%E5%87%BAE%28x%29%E4%B8%BA%E4%BB%80%E4%B9%88%E4%B8%8D%E5%AF%B9%E5%93%AA%E9%87%8C%E9%94%99%E4%BA%86%3F)
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