2.
\((1)\) 已知随机变量\(X{~}B(6{,}\dfrac{1}{3})\),那么\(D(X){=}\) ______ .
\((2)\) 已知\(x\)与\(y\)之间的几组数据如表:则由表数据所得线性回归直线必过点______ .
\(x\) | \(3\) | \(4\) | \(5\) | \(6\) |
\(y\) | \(2{.}5\) | \(3\) | \(4\) | \(4{.}5\) |
\((3)\) 若函数\(f(x){=}x^{3}{-}3{ax}{+}a\)有三个不同的零点,则实数\(a\)的取值范围是______.
\((4)\)若函数\(f(x){=}a^{2}x^{3}{+}ax^{2}{-}x\)在\({[}1{,}3{]}\)上不单调,则\(a\)的取值范围为 ______