An unbiased estimator of a population parameter is an estimator whose expected value is equal to the population parameter to be estimated.

If an estimator is said to be unbiased, then the population mean equals the sample mean.

In Stratified random sampling show that sample mean is NOT an unbiased estimator of (10) population mean. Hence define an unbiased estimator of population mean and obtain its variance.

difference between parameter and estimator

In SRSWOR for variables , in usual notations prove that Sample mean is an unbiased estimator of population mean.

We say that a point estimator is unbiased if which of the following is true? Its sampling distribution is normal. The standard deviation of its sampling distribution decreases as the sample size increases. Its value is always equal to the parameter it estimates. Its sampling distribution is centered exactly at the parameter it estimates.