A sample size calculation for logistic regression involves complicated formulae. This paper suggests use of sample size formulae for comparing means or for comparing proportions in order to calculate the required sample size for a simple logistic regression model. One can then adjust the required sample size for a multiple logistic regression model by a variance inflation factor. This method re...

Exact power and sample size calculation for bioequivalence studies with high order crossover designs using statistical software nQuery are presented. Such calculation can be very easily performed, and thus provides a convenient tool for practical usage.

in the present work, an engineering method is developed to predict laminar and turbulent heating-rate solutions for blunt reentry spacecraft at hypersonic conditions. the calculation of aerodynamic heating around blunt bodies requires alternative solution of inviscid flow field around the hypersonic bodies. in this paper, the procedure is of an inverse nature, that is, a shock wave is assumed a...

In clinical research, parameters required for sample size calculation are usually unknown. A typical approach is to use estimates from some pilot studies as the true parameters in the calculation. This approach, however, does not take into consideration sampling error. Thus, the resulting sample size could be misleading if the sampling error is substantial. As an alternative, we suggest a Bayes...

in this paper, optimal distributed control of the time-dependent navier-stokes equations is considered. the control problem involves the minimization of a measure of the distance between the velocity field and a given target velocity field. a mixed numerical method involving a quasi-newton algorithm, a novel calculation of the gradients and an inhomogeneous navier-stokes solver, to find the opt...

introduction radiotherapy with small fields is used widely in newly developed techniques. additionally, dose calculation accuracy of treatment planning systems in small fields plays a crucial role in treatment outcome. in the present study, dose calculation accuracy of two commercial treatment planning systems was evaluated against monte carlo method. materials and methods siemens once or linea...

The δN formalism is considered for the calculation of the evolution of the curvature perturbations in generalized multi-field inflation models. The result is consistent with the usual calculation of the standard kinetic term. For the calculation of the generalized kinetic term, we improved the definition of the adiabatic field. Our calculation improves the usual calculation of Ṙ based on the fi...

background and purpose: sample size and its determination is one of the most important problems in health researches. calculating sample size for prevalence studies is one of the common questions of sample size topics. minimum sample size with least complexity is desirable in order to achieve the basic goal of these studies. this study aims to compare two formulas of sample size calculation for...

BACKGROUND In radiotherapy treatment, the calculation of radiation dose distribution in target volume lead to an optimum set of planning parameters. This worked has been aimed to compare two photon beam dose calculation algorithms in the Oncentra Treatment Planning system for Varian Linear Accelerator, to assure the quality of treatment planning. METHODS Monitor Units to be delivered on norma...