Background: Two main issues that challenge model building are number of Events Per Variable and multicollinearity among exploratory variables. Our aim is to review statistical methods that tackle these issues with emphasize on penalized Lasso regression model.  The present study aimed to explain problems of traditional regressions due to small sample size and m...

the waiting time between children births are called tempo. this phenomenon plays a crucial role in the child and mother health. the purpose of the present study is determination of factors which influence this variable of interest. a significance level of 5% and power of 80% considered to calculate the required sample size for this cross sectional study. the sample size of 124 women determined ...

objective: tempo is the average waiting time to next birth for a woman. role of fertility as the most important phenomenon determining population fluctuations due to the studies of it compared with other demographic phenomena be important and review the multifarious socioeconomic factors of it share  a large effective population studies. general purpose of this study is fitting the cox model to...

In this paper, we are concerned with the estimation of the discrepancy between two treatments when right-censored survival data are accompanied with covariates. Conditional confidence intervals given the available covariates are constructed for the difference between or ratio of two median survival times under the unstratified and stratified Cox proportional hazards models, respectively. The pr...

aim : to determine the associated factors of reflux duration, using quantile regression model. background : reflux is one of the most prevalent gastrointestinal disorders.  statistical tools are widely used to assess the associated factors on reflux severity and frequency. patients and methods : a door to door questionnaire has been used to evaluate gastrointestinal symptoms including reflux an...

Cox regression model serves as a statistical method for analyzing the survival data, which requires some options such as hazard proportionality. In recent decades, artificial neural network model has been increasingly applied to predict survival data. This research was conducted to compare Cox regression and artificial neural network models in prediction of kidney transplant survival. The prese...

original article   extended exposure to noise can cause permanent hearing damage. this study aimed to determine the incidence time of hearing loss and its effective factors in workers exposed to noise. this retrospective cohort study, was conducted on a total of 273 workers in various sectors of kerman copper by-industries co. their hearing status and the incidence of hearing loss (hearing thre...

Point processes in time have a wide range of applications that include the claims arrival process insurance or analysis queues operations research. Due to advances technology, such samples point are increasingly encountered. A key object interest is local intensity function. It has straightforward interpretation allows understand and explore data. We consider functional approaches for processes...