RESUMO
In this paper, we propose a partial randomized response technique to collect reliable sensitive data for estimation of population proportion in ranked set sampling (RSS) scheme using auxiliary information. The idea is to increase confidence and (or) co-operation of the respondents by providing them the option of both 'direct' and 'randomized' response for the inquired sensitive question. This option is quite logical because perception of sensitive (insensitive) inquiry can vary among respondents. The properties of the proposed method are discussed and compared with existing randomized response techniques. Cost analysis is also carried out to prove supremacy of the suggested method. Finally, an application to clinical trial on AIDS is included.