What Is the Joint PDF for Durations of Bulbs with Exponential Distribution?

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    Determination Pdf
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Discussion Overview

The discussion centers on determining the joint probability density function (pdf) for the durations of bulbs that follow an exponential distribution. The scope includes theoretical considerations regarding the properties of independent random variables and their distributions.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant asks for help in determining the joint pdf of the durations of n bulbs with exponential distribution.
  • Another participant questions whether the durations can be assumed to be independent, suggesting that this assumption would simplify the problem.
  • A subsequent reply confirms that the durations can indeed be considered independent.
  • Another participant prompts discussion about the properties of distributions of independent random variables.
  • A final post proposes a specific form for the joint pdf, stating it as f(t_1,t_2...t_n)=\lambda^n e^{-\lambda \sum_{i=1}^{n}t_i}, seeking validation of this answer.

Areas of Agreement / Disagreement

Participants generally agree on the independence of the durations, but the correctness of the proposed joint pdf remains contested, as no consensus is reached on its validity.

Contextual Notes

The discussion does not clarify the assumptions underlying the independence of the durations or the derivation of the proposed joint pdf. There may be unresolved mathematical steps related to the formulation of the joint pdf.

Gp7417
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Determination of a Joint pdf

Hi all! Someone can help me with this problem?

The duration of a certain type of bulbs has a exponential distribution with known parameter \lambda. Consider a set of n bulbs. Which is the joint pdf of the durations t_{i} of the n bulbs?
 
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Can you assume that the durations' distributions are independent? If so, there shouldn't be a problem.
 
Yes the durations can be indipendent.
 
What do you know about distributions of independent random variables?
 
Is this the right answer?
f(t_1,t_2...t_n)=\lambda^n e^{-\lambda \sum_{i=1}^{n}t_i}
 

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