A random variable X has a probability density function, \[{\text{f}}\left( {\text{x}} \right) = \left\{ {\begin{array}{*{20}{c}} {{\text{k}}{{\text{x}}^{\text{n}}}{{\text{e}}^{ - {\text{x}}}};}&{{\text{x}} \geqslant {\text{0}}} \\ {0;}&{{\text{otherwise}}} \end{array}} \right.\] (n is an integer) with mean 3. The values of {k, n} are
A. $$\left\{ {\frac{1}{2},\,1} \right\}$$
B. $$\left\{ {\frac{1}{4},\,2} \right\}$$
C. $$\left\{ {\frac{1}{2},\,2} \right\}$$
D. $$\left\{ {1,\,2} \right\}$$
Answer: Option C
This Question Belongs to Engineering Maths >> Probability And Statistics
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