A Random Variable X Is Exponentially Distributed with a Mean $\operatorname { Pr } ( 1 \leq X \leq 3 )$

question 66

Multiple Choice

A random variable X is exponentially distributed with a mean of 2. Find $\operatorname { Pr } ( 1 \leq X \leq 3 )$

• A) \(\frac { 1 } { 2 }\) ( \(\mathrm { e } ^ { - 1 }\) - \(\mathrm { e } ^ { - 3 }\) )
• B) \(\frac { 1 } { 2 }\) \(e ^ { - 1 / 2 }\)
• C) \(\frac { 1 } { 2 }\) \(e ^ { - 3 / 2 }\)
• D) \(e ^ { - 1 / 2 }\) - \(e ^ { - 3 / 2 }\)
• E) none of these