Two-phase sampling is often used in a wide variety of surveys. Variance estimation from a two-phase sample has been a subject of active research. The re-sampling method of variance estimation has been used for this problem. However, the method confronts a challenging problem when the first phase sampling fraction is high. In the extreme (but not uncommon) case some first-phase strata are take-a...

a chromium electroplating bath with the ability to produce homogenous mist was used to evaluate parameters influencing hexavalent chromium (cr+6) mist sampling methods. the results of 48 cr+6mist samples collected using the u.s. national institute for occupational safety and health method 7600showed that cr+6concentration was higher: (1) for sampling by closed-face filter cassettes than for sam...

A method for direct sampling of the exponential moments of canonical phase from the data recorded in balanced homodyne detection is presented. Analytical expressions for the sampling functions are shown which are valid for arbitrary states. A numerical simulation illustrates the applicability of the method and compares it with the direct measurement of phase by means of double homodyning.

To estimate the population mean with imputation, i.e. the technique of substituting missing data, there are a number of techniques available in literature like Ratio method of imputation, Compromised method of imputation, Mean method of imputation, Ahmed’s methods of imputation, F-T methods of imputation and so on. If population mean of auxiliary information is unknown then these methods are no...

We propose a jackknife variance estimator for the population average from two, two-phase samples after imputation. The jackknife method has long been used to estimate and reduce bias, but has now become a valuable tool for variance estimation. We apply two different sampling methods, (simple random sampling and stratified random sampling) to derive jackknife variance estimators for the twosampl...