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(Lamperti<ref group="Notes" >Private communication.</ref>) An urn contains exactly 5000 balls, of which an unknown number <math>X</math> are white and the rest red, where <math>X</math> is a random variable with a probability distribution on the integers 0, 1, 2, ..., 5000.
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<ul style="list-style-type:lower-alpha"><li> Suppose we know that <math>E(X) = \mu</math>.  Show that this is enough to allow us to
\newcommand{\mat}[1]{{\bf#1}}
\newcommand{\exref}[1]{\ref{##1}}
\newcommand{\secstoprocess}{\all}
\newcommand{\NA}{{\rm NA}}
\newcommand{\mathds}{\mathbb}</math></div> (Lamperti<ref group="Notes" >Private communication.</ref>) An
urn contains exactly 5000 balls, of which an unknown number <math>X</math> are white and the rest red, where <math>X</math>
is a random variable with a probability distribution on the integers 0, 1, 2, \dots, 5000.
<ul><li> Suppose we know that <math>E(X) = \mu</math>.  Show that this is enough to allow us to
calculate the probability that a ball drawn at random from the urn will be white.  
calculate the probability that a ball drawn at random from the urn will be white.  
What is this probability?
What is this probability?

Latest revision as of 21:21, 14 June 2024

(Lamperti[Notes 1]) An urn contains exactly 5000 balls, of which an unknown number [math]X[/math] are white and the rest red, where [math]X[/math] is a random variable with a probability distribution on the integers 0, 1, 2, ..., 5000.

  • Suppose we know that [math]E(X) = \mu[/math]. Show that this is enough to allow us to calculate the probability that a ball drawn at random from the urn will be white. What is this probability?
  • We draw a ball from the urn, examine its color, replace it, and then draw another. Under what conditions, if any, are the results of the two drawings independent; that is, does
    [[math]] P({{\rm white},{\rm white}}) = P({{\rm white}})^2\ ? [[/math]]
  • Suppose the variance of [math]X[/math] is [math]\sigma^2[/math]. What is the probability of drawing two white balls in part (b)?

Notes

  1. Private communication.