The Syrian hamster has an average life span of two to three years. Although uncommon, these hamsters can sometimes live up to five years. A hamster's life span can be extended to a degree by providing it with a clean environment and fresh food daily. Continue Reading.
and substituting the estimate for gives. which is an unbiased estimator of the variance of the mean in terms of the observed sample variance and known quantities. Note that, if the autocorrelations are identically zero, this expression reduces to the well-known result for the variance of the mean for independent data.
For example, we use the sample mean as an unbiased estimator for the population mean. (Mathematically, it can be shown that the expected value of the sample mean is equal to the population mean). In the case of estimating the population standard deviation, the sample standard deviation is an unbiased estimator too.