APPLICATION OF BOOTSTRAP METHOD FOR EVALUATING DISCREPANT LEVELS OF RADIUM-226
 IN FORAGE PALM (Opuntia spp)

Cleomacio Miguel da SILVA[1]

Ademir AMARAL[2]

Romilton dos Santos AMARAL [3]

José Araújo dos SANTOS JÚNIOR[4]

José Wilson VIEIRA[5]

§    ABSTRACT: The distribution of natural radionuclides in samples from typically anomalous environments has generally a great significant asymmetry, as a result of outlier. For diminishing statistic fluctuation researchers, in radioecology, commonly use geometric mean or median, once the average has no stability under the effect of outliers. On the other hand, Efron presented a non-parametric method the so-called bootstrap that can be used to decrease the dispersion around the central-tendency value. In this context, the present study had as an objective to evaluate the application of the non-parametric bootstrap method (BM) for determining the average concentration of 226Ra in cultivated forage palms (Opuntia spp.) in soils with uranium anomaly distributed on the dairy milk farms, localized in Pernambuco-Brazil, as well as discussing the utilization of this method in radioecology. The results of 226Ra in samples of forage palm varied from 1,300 to 25,000 mBq.kg-1 (dry matter), with arithmetic average of 5,965.86± 5,903.05 mBq/kg. The result obtained for this mean by BM was 5,963.82 ± 1,202.96 mBq.kg-1 (dry matter). Thus, the BM permitted reaching a robust arithmetic mean, minimizing the effects of the outliers.

§     KEYWORDS: Bootstrap, radium-226, forage palm



[1] Departamento de Física, Universidade Frederal Rural de Pernambuco – UFRPE, CEP: 52171-900, Recife, PE, Brasil. E‑mail: cleomacio@ig.com.br

[2] Grupo de Estudos em Radioproteção e Radioecologia (GERAR), Departamento de Energia Nuclear, Universidade Frederal de Pernambuco – UFPE, CEP: 50740-540, Recife, PE, Brasil. E‑mail: amaral@ufpe.br

[3] Departamento de Energia Nuclear, Universidade Frederal Rural de Pernambuco – UFPE, CEP: 50740-540, Recife, PE, Brasil. E‑mail: romilton@ufpe.br

[4] Departamento de Química, Universidade Frederal Rural de Pernambuco – UFRPE, CEP: 52171-900, Recife, PE, Brasil. E‑mail: jaraujo@ufpe.br

[5] Departamento de Física, CEFET-PE, CEP: 50740-540, Recife, PE, Brasil. E‑mail: wilson@yahoo.com.br