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Questions › JNU › JNU SSS 2018 › Q23
1 mark, −0.25Statistics › Random variables and standard distributions › Exponential and gamma distributionsEasyabout 1 min

JNU SSS 2018 Question 23: Random variables and standard distributions

A random variable XXX has the following probability density function : f(x)=e−xf(x) = e^{-x}f(x)=e−x for 0<x<∞0 < x < \infty0<x<∞ f(x)=0f(x) = 0f(x)=0 for x≤0x \leq 0x≤0

The mean of XXX is equal to

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A random variable X has the following probability density function: f(x) = e^(-x) for 0 < x < ∞ f(x) = 0 for x ≤ 0 The mean of X is equal to (A) 1/e (B) 1 (C) e (D) None of the above

Also written as: A random variable X has the following probability density function: f(x) = e^(-x) for 0 < x < inf f(x) = 0 for x <= 0 The mean of X is equal to

Random variables and standard distributions has come up 173 times in 7 exams since 2005.

What this question tests

This question is on Exponential and gamma distributions, part of Random variables and standard distributions in Statistics.

Waiting times, memorylessness and sums of exponentials.

TestStop has 7 past-paper questions on this subtopic.

Practise Random variables and standard distributionsMore on Exponential and gamma distributions

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Question from the JNU SSS 2018 paper. Solutions are TestStop's own. Not affiliated with or endorsed by any examination authority.