The sum of a random sample from a population. The expected value of the sample sum is the sample size times the population mean. For sampling with replacement, the SE of the sample sum is the population standard deviation, times the square-root of the sample size. For sampling without replacement, the SE of the sample sum is the finite-population correction ((N−n)/(N−1))^½ times the SE of the sample sum for sampling with replacement, with N the size of the population and n the size of the sample.