this study aims at testing the degree of stability for beta coefficient across time, depending on the information available from tehran bourse. where beta coefficient was calculated using the market model developed by sharp on 1963, which applies by performing a simple linear regression between the company’s and the market returns, where beta coefficient is the slope of this regression. in this...

introduction: estimation of cation exchange capacity (cec) with reliable soil properties can save time and cost. pedotransfer function (ptf) is a common method in estimating certain soil properties (e.g. cec) that has been wieldy used for many years. one of the common techniques that have been used to develop ptfs is multiple linear regressions. in this method, all easily obtained soil properti...

The functional coefficient partially linear regression model is a useful generalization of the nonparametric model, partial linear model, and varying coefficient model. In this paper, the local linear technique and the L1 method are employed to estimate all the functions in the functional coefficient partially linear regression model. The asymptotic properties of the proposed estimators are stu...

OBJECTIVE To test the hypothesis that audible television is associated with decreased parent and child interactions. DESIGN Prospective, population-based observational study. SETTING Community. PARTICIPANTS Three hundred twenty-nine 2- to 48-month-old children. MAIN EXPOSURES Audible television. Children wore a digital recorder on random days for up to 24 months. A software program inco...

This paper is an attempt to assess the potential and usefulness of ANN based modeling for evaporation prediction from a reservoir, where in classical and empirical equations failed to predict the evaporation accurately. The meteorological data set of daily pan evaporation, temperature, solar radiation, relative humidity, wind speed is used in this study. The performance of feed forward back pro...

introduction: the development of an appropriate model for the quality control of an industrial wastewater treatment system can save the time as well as the cost. this study was performed to determine an appropriate model in order to predict the cod and tkn parameters by bod5 and nh4+ in the meybod industrial estate waste water treatment plant (wwtp). methods: this descriptive – analytical study...

Random coe cient regression models have been applied in di erent elds and they constitute a unifying setup for many statistical problems. The nonparametric study of this model started with Beran and Hall (1992) and it has become a fruitful framework. In this paper we propose and study statistics for testing a basic hypothesis concerning this model: the constancy of coe cients. The asymptotic be...