Probability Distribution of X, Y & N(i): Questions & Answers

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Discussion Overview

The discussion revolves around identifying the probability distributions for various random variables X, Y, and N(i) in different scenarios involving urns, dice throws, and battery durations. The scope includes theoretical aspects of probability distributions and their applications in specific problems.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant asks about the distributions for X, Y, and N(i) in four specific cases involving urns, dice, and batteries.
  • Another participant suggests that the distribution for X in the first case is presumably uniform but notes insufficient information.
  • For the second case, a participant identifies the distribution as geometric.
  • A participant challenges the correctness of the approach to the third case, stating it was wrong but does not clarify the issue with the question itself.
  • In the fourth case, the same participant again identifies the distribution as geometric.

Areas of Agreement / Disagreement

Participants express disagreement regarding the third case, with one participant stating their previous answer was incorrect but not addressing the original question's validity. There is no consensus on the distributions for all cases, particularly the third.

Contextual Notes

Participants note limitations in the information provided for the first case, which may affect the determination of the distribution. The third case remains unresolved in terms of the correct approach.

Who May Find This Useful

Individuals interested in probability theory, particularly those studying distributions in various contexts such as games of chance and reliability of components.

JohanL
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I have some simple questions about distributions in probability.
what are the distributions for X, Y and N(i) in these cases:

1. You have k urns and n balls. X is the number of balls in one urn.

2. You throw two dices until you get a pair of sixes. X is the number of throws.

3. You have three batteris A,B and C. There durations (? how long they last. I am from sweden) have exponential distributions with DIFFERENT parameters. If you first use A and B in a lamp what is the distribution for X, the time the
lamp works. Then you replace the nonworking battery with battery C. What is the distribution for Y, the time the lamp works after the exchange.

4. You throw one dice over and over again. Let N(i) be the throw when you get i for the first time. What is the distribution for N(i).

Thank you.

I have no problem to do the calculations when i know the distributions. The hard point for me is to figure out the distributions...my book isn't so good.
 
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1. not enough information. you presumably uniformly distributed.

2 is geometric

3. scratch 3, that was wrong.

4. geometric again.
 
Last edited:
Thx
But what's wrong with 3...its a problem from the book.
 
my answer was wrong, not the question.
 

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