Standard Error of the Mean

The standard error of the mean is a number that represents the variability within a sampling [Page 1431]distribution. In other words, it is how measurements collected from different samples are distributed around the mean of the total population from which the sample measurements could be taken. The mean of each sample of measurements, therefore, is an estimate of the population mean. Although the means from each sample provide an estimate of the mean of the entire population, measurements collected from numerous samples are quite unlikely to be equivalent. This raises the question of how well each sample mean represents the true population mean. That accuracy can be estimated by calculating the standard error of the mean, which provides an indication of how close the sample ...