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March 11th, 2012, 06:31 PM  #1 
Newbie Joined: May 2010 Posts: 12 Thanks: 0  Expected Value
How can I calculate the expected value of with ? Thanks 
March 12th, 2012, 02:38 PM  #2 
Global Moderator Joined: May 2007 Posts: 6,787 Thanks: 708  Re: Expected Value
You can't. You need to know the distribution function for Y.

March 17th, 2012, 09:27 PM  #3 
Newbie Joined: May 2010 Posts: 12 Thanks: 0  Re: Expected Value
sorry I forgot the distribution, the distribution is Thanks 
March 18th, 2012, 01:09 PM  #4 
Global Moderator Joined: May 2007 Posts: 6,787 Thanks: 708  Re: Expected Value
Unless we are at cross purposes (I am not quite sure what the random variable is  you use y and Y[with overhead bar]), you can't get an expectation, since y has a nonzero probability of = 1.

March 18th, 2012, 05:08 PM  #5 
Newbie Joined: May 2010 Posts: 12 Thanks: 0  Re: Expected Value
Y denote a Bernoulli random variable with . I want estimate the odds ratio . I know that is a unbiased estimator of . I want to show that is not a unbiased estimator of and for that reason I want know 
March 19th, 2012, 02:29 PM  #6 
Global Moderator Joined: May 2007 Posts: 6,787 Thanks: 708  Re: Expected Value
Ybar being an unbiased estimator is (at least my understanding) is that you took a sample of a certain size and computed the mean. If my understanding is correct, then Ybar has a nonzero probability of = 1, so the estimate you are concerned about would be infinite.


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