Question

Let X be a random variable exponentially distributed with parameter λ > 0. The probability density function of X is given by :
f(x) = \left\\{ \begin{array}{ll} \lambda e^{-\lambda x,} & x \ge0 \\\ 0 & \text{otherwise} \end{array} \right.
If 5E(X) = Var (X), where E (X) and Var (X) indicate the expectation and variance of X, respectively, the value of λ is _____
(rounded off to one decimal place).

Answer 1

The correct answer is 0.2