设随机变量X的数学期望EX存在,且EX=a,EX平方=b,若c为常数,则D(cX)=
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![设随机变量X的数学期望EX存在,且EX=a,EX平方=b,若c为常数,则D(cX)=](/uploads/image/z/7167126-30-6.jpg?t=%E8%AE%BE%E9%9A%8F%E6%9C%BA%E5%8F%98%E9%87%8FX%E7%9A%84%E6%95%B0%E5%AD%A6%E6%9C%9F%E6%9C%9BEX%E5%AD%98%E5%9C%A8%2C%E4%B8%94EX%3Da%2CEX%E5%B9%B3%E6%96%B9%3Db%2C%E8%8B%A5c%E4%B8%BA%E5%B8%B8%E6%95%B0%2C%E5%88%99D%EF%BC%88cX%EF%BC%89%3D)
设随机变量X的数学期望EX存在,且EX=a,EX平方=b,若c为常数,则D(cX)=
设随机变量X的数学期望EX存在,且EX=a,EX平方=b,若c为常数,则D(cX)=
设随机变量X的数学期望EX存在,且EX=a,EX平方=b,若c为常数,则D(cX)=
D(cX)
=c²D(X)
=c²( E(X²) - (EX)² )
=c²(b-a²)
D(cX)
=c²D(X)
=c²( E(X²) - (EX)² )
=c²(b-a²)
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