# Tag Info

## Hot answers tagged expected-value

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### Expected value of the square root of a lognormal variable

The square root of a lognormal is itself lognormal. Indeed $Y^p$ is lognormal more generally. Note that if $X\sim N(\mu,\sigma^2)$ then $Y=\exp(X)$ is lognormal with the same parameters and vice versa....
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### Is the expectation of a random vector multiplied by its transpose equal to the product of the expectation of the vector and that of the transpose

To confirm a claim is not true, you don't "prove it". Instead, just provide a counterexample would be sufficient. You are actually on the right track. Any random vector $z$ with positive ...
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### Expected value of the square root of a lognormal variable

If Wikipedia is trustworthy enough for you, it says that $$E(X^n) = \text{exp}\big(n\mu+\frac{1}{2}n^2\sigma^2\big)$$ for real or complex $n$, so you can use this formula with $n=\frac{1}{2}$. ...
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### Is a product that has 4.9 stars from ten customers better than one that has 4.5 stars from a hundred customers?

Clearly, several online platforms like Trip Advisor etc. have implemented a sorting system that trades these two things off. If they all did it the same way I'd guess one might consider that a ...
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### Probability algorithm on strings

Ok, so you have strings $Z_n$ that are exactly half 0s and half 1s and you have $X_n$ that have exactly one more 1. One way to generate these sorts of strings is to generate a $Z_n$ uniformly at ...
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