Sample size for estimating the mean concentration of organisms in ballast water.
We consider the computation of sample sizes for estimating the mean concentration of organisms in ballast water. Given the possible heterogeneity of their distribution in the tank, we adopt a negative binomial model to obtain confidence intervals for the mean concentration. We show that the results obtained by Chen and Chen (2012) in a different set-up hold for the proposed model and use them to develop algorithms to compute sample sizes both in cases where the mean concentration is known to lie in some bounded interval or where there is no information about its range. We also construct simple diagrams that may be easily employed to decide for compliance with the D-2 regulation of the International Maritime Organization (IMO).
Departamento de Estatística, Instituto de Matemática e Estatística, Universidade de São Paulo, Brazil. Electronic address: eliardo@ime.usp.br.
Eliardo G
EG
Costa
Departamento de Oceanografia Biológica, Instituto Oceanográfico, Universidade de São Paulo, Brazil. Electronic address: rubens@usp.br.
Rubens M
RM
Lopes
Departamento de Estatística, Instituto de Matemática e Estatística, Universidade de São Paulo, Brazil. Electronic address: jmsinger@ime.usp.br.
Julio M
JM
Singer
D059001:Aquatic Organisms; D015233:Models, Statistical; D018401:Sample Size; D012623:Seawater; D012767:Ships
Bounds on absolute and relative errors; Confidence interval; Coverage probability; Negative binomial distribution