Summary
Murthy and Nanjamma [4] studied the problem of construction of almost unbiased ratio estimators for any sampling design using the technique of interpenetrating subsamples. Subsequently, Rao [7], [8] has given a general method of constructing unbiased ratio estimators by considering linear combinations of the two simple estimators based on the ratio of means and the mean of ratios. However, it is difficult to choose an optimum weight (Rao [9]) which minimizes the variance of the combined estimator since the weights are random in certain cases. In this note, we consider a different method of combining these estimators and obtain a general class of almost unbiased ratio estimators of which Murthy and Nanjamma's is a particular case and derive an optimum in this class. The case of simple random sampling where a similar class of almost unbiased ratio estimators can be developed is briefly discussed. The results are illustrated by means of simple numerical examples.
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References
Goodman, L. A. and Hartley, H. O. (1958). The precision of unbiased ratio-type estimators,J. Amer. Statist. Ass.,53, 491–509.
Hartley, H. O. and Ross, A. (1954). Unbiased ratio estimators,Nature,174, 270–271.
Murthy, M. N. (1967).Sampling Theory and Methods, Statistical Publishing Society, Calcutta.
Murthy, M. N. and Nanjamma, N. S. (1959). Almost unbiased ratio estimators based on interpenetrating sub-sample estimates,Sankhyã,21, 381–392.
Nieto de Pascual, J. (1961). Unbiased ratio estimators in stratified sampling,J. Amer. Statist. Ass.,56, 70–87.
Rao, J. N. K. (1969). Ratio and regression estimators,New Developments in Survey Sampling (eds. N. L. Johnson and H. Smith), Wiley-Interscience, 213–234.
Rao, T. J. (1966). On certain unbiased ratio estimators,Ann. Inst. Statis.. Math.,18, 117–121.
Rao T. J. (1979). Unbiasedness and convexity in ratio estimation,Technical Report, Math. Stat. Unit, Indian Statistical Institute, Calcutta.
Rao, T. J. (1980). A note on unbiasedness in ratio estimation, to appear.
Sukhatme, P. V. (1954).Sampling Theory of Surveys with Applications, Iowa State College Press, Ames, Iowa.
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Rao, T.J. On a class of almost unbiased ratio estimators. Ann Inst Stat Math 33, 225–231 (1981). https://doi.org/10.1007/BF02480936
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DOI: https://doi.org/10.1007/BF02480936