Some Product Moments Useful in Sampling Theory
K. Raghunandanan, R. Srinivasan · Journal of the American Statistical Association · 1973
General methods are developed for finding the mathematical expectation of and where X pj denotes the pth (p=1,2,···,k) character of the jth (j=1,2,···, N) unit of a finite population, is the sample mean of the pth character based on a random sample of size n, and is the corresponding population mean. Methods for unbiasedly estimating the product moments are also presented.