A Probability Problem Involving 6 Random Variables

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SUMMARY

The discussion focuses on calculating probabilities involving six independent and identically distributed continuous random variables, denoted as X_1 through X_6. Specifically, it addresses two conditional probabilities: (a) P{X_6 > X_1 | X_1 = max(X_1, ..., X_5)} and (b) P{X_6 > X_2 | X_1 = max(X_1, ..., X_5)}. The participant correctly identifies that the calculation for (a) involves determining if X_6 is the maximum of all six variables. For (b), the participant notes the independence of the event X_6 > X_2 from the condition provided, leading to the use of joint probability density functions.

PREREQUISITES
  • Understanding of independent and identically distributed (i.i.d.) random variables
  • Knowledge of conditional probability and its applications
  • Familiarity with continuous probability distributions and their density functions
  • Ability to perform double integrals for joint probability calculations
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  • Study the properties of independent random variables in probability theory
  • Learn about conditional probability and its implications in statistical analysis
  • Explore continuous probability distributions, focusing on their density functions
  • Practice solving double integrals in the context of joint probability distributions
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Homework Statement
Let [itex]X_1, \ldots, X_6[/itex] be a sequence of independent and identically distributed continuous random variables. Find

(a) [itex]P\{X_6 > X_1 \, | \, X_1= \max(X_1, \ldots, X_5)\}[/itex]
(b) [itex]P\{X_6 > X_2 \, | \, X_1 = \max(X_1, \ldots, X_5)\}[/itex]

The attempt at a solution
(a) is the probability that [itex]X_6 = \max(X_1, \ldots, X_6)[/itex] right? How would I determine this probability? In (b), the event [itex]X_6 > X_2[/itex] is independent of [itex]X_1 = \max(X_1, \ldots, X_5)[/itex] right? If it is, the probability is:

[tex]\int_{-\infty}^{\infty} \int_{x_1}^{\infty} f(x_6, x_1), \, dx_6 \, dx_1[/itex]<br /> <br /> where [itex]f(x_6, x_1) = f(x_6)f(x_1)[/itex] since the random variables are independent. Right?[/tex]
 
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[tex]\int_{-\infty}^{\infty} \int_{x_1}^{\infty} f(x_6, x_1), \, dx_6 \, dx_1[/itex]<br /> <br /> where [itex]f(x_6, x_1) = f(x_6)f(x_1)[/itex] since the random variables are independent. Right?[/tex]
[tex] <br /> I screwed up. [itex]x_1[/itex] should be [itex]x_2[/itex] in the above.[/tex]
 

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