RATIO estimators are frequently employed in sample surveys when estimating the population mean Ȳ of a variate y with the help of the known population mean X of a correlated variable x. Confining ourselves to the case of a simple random sample of n pairs y i, X i from a population of N pairs, various ratio estimators of Ȳ can be formed of which the most important ones are y = Xȳ/x and ŷ = Xr, where ȳ, x and r are the arithmetic means of the sample of y i/x i and y i/x i, respectively.