It is presented two sampling methods for selecting a sample of children of a given age range, living in a geographical area of interest, to estimate vaccinal coverage: the R.H. Henderson and T. Sundaresan method, the Department of Epidemiology and Quantitative Methods of National Public Health School method. A third method of selection is then proposed. The geographical area of interest is divided into parts which are used as primary sampling units (PSU’s). First method: 30 PSU’s are selected with […]

Zippin’s procedure is one of the most accurate methods used to estimate total populations from removal trapping data. However, explicit algebraic solutions of the maximum likelihood equations do not exist. Hitherto they have been obtained from graphs known as Zippin charts. In this paper a Newton-Raphson procedure is used to obtain numerical solutions to the equations. Comparisons with the classical method show some differences in the parameters, particularly in the estimation of the standard error.