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definition

The mathematical expectation of the estimator is equal to the estimated parameter, so it is called unbiased estimation.

Settings? =g(X 1, X2, ..., Xn) is the point estimator of unknown parameter A, if? satisfy

e(？ )=

A

What's it called? For a man

unbiased estimator

Otherwise, it is a biased estimator.

Note: Unbiased estimation means that the system error is zero.