# What is a zero-mean error?

Hey guys,

What is a zero mean error in statistics?

Hope this is enough information? I think it's a basic question though :).

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This type of question would fit better on a site like maths.stackexchange.com –  Loop Space Apr 7 '11 at 11:54

The error is the difference between the estimate $\hat \theta$ and the true value of the statistic $\theta$.
Mean-zero error means $E[\hat \theta - \theta] = 0$, i.e. $\hat \theta$ is an unbiased estimator of $\theta$.