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 an unbiased estimate, the sum of the signed deviations across the entire set of all observations from the overall sample mean is always zero, and the expected, mean, or average deviation is also zero; conversely, a nonzero average deviation quantifies the bias exhibited by the estimate.tatistics of the distribution of deviations are used as measures of statistical dispersion. 1  Standard deviation is the frequently used measure of dispersion: it uses squared deviations, and has desirable properties, but is not robust.