In a lifetime model where lifetimes are i.i.d. exponential with mean θ, the expected value of the k-th order statistic X_(k) is equal to which expression?

In a lifetime model where lifetimes are i.i.d. exponential with mean θ, the expected value of the k-th order statistic X_(k) is equal to which expression?

• A. θ * sum_{i=1}^k (1/i)
• B. θ * k
• C. θ / k
• D. θ * sum_{i=1}^k (1/(i+1))

Answer: (A)