Can E(y/x) be determined if E(1/x) and E(y) are known?

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SUMMARY

The discussion centers on the relationship between expected values of random variables, specifically whether E(y/x) can be determined if E(1/x) and E(y) are known. It is established that E(1/x) equals a and E(y) equals b, leading to the conclusion that E(y/x) equals b/a only under the condition that x and y are independent random variables. If x and y are not independent, the relationship does not hold, as illustrated by the example where y equals x.

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zli034
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say, E(1/x)=a and E(y)=b. a and b are constants and x and y are random variables.

Can I say E(y/x)=b/a? Thanks.
 
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Only if x and y are independent. If not, anything can happen - simple example y=x.
 
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