Sampling design providing unbiased new product estimators

M. R. Espejo & J. S. Penas
A sampling design is proposed for which a new product estimator is unbiased, and therefore it is possible to build associate sampling schemes. This result completes the theory of sampling schemes providing unbiased ratio estimators and regression estimators given respectively for the first time by Hájek (1949) and Singh and Srivastava (1980).