# Recent content by ravn

1. ### Biased and un-biased estimators.

I am working with the Rayleigh-distribution and note that on Wikipedia they say that s^2 = 1/(2N) sum x_i^2 is an unbiased estimator of sigma^2. Now they also say that s = sqrt(s^2) is a biased estimator of sigma. How can this be?? If one is unbiased, why isn't the other one? I mean, you...
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