When experimental units, on a cross-sectional or a longitudinal study, are followed up periodically, the event(s) of interest may only be known to have occurred between two dates of follow-up. In this case data are usually presented in form of counts of events in each of the follow-up intervals (grouped data). Furthermore, in studies of survival, subjects may be at risk of failure due to more t...

The Weibull distribution is widely used in reliability and life data analysis due to its versatility. And, this distribution has been considered as a popular life time distribution which describes modeling phenomena with monotonic failure rates of components. Depending on the values of the parameters it can be used to model a variety of life behaviors. In this paper, reliability measures such a...

In wood engineering, lower quantile estimation is vital to the safety of the construction with wood materials. In this thesis, we will first study the censored Weibull maximum likelihood estimate (MLE) of the lower quantile as in the current industrial standard D5457 (ASTM, 2004a) from a statistical point of view. According to our simulations, the lower quantile estimated by the censored Weibul...

The objective of this study was to evaluate the ability of three statistical distributions to characterize the vertical distribution of foliage mass in canopies of even-aged loblolly pine stands, based on airborne-scanning light detection and ranging (LiDAR) data. The functions were the Weibull and SB distributions and a mixture of the lognormal and Weibull distributions. Results indicated that...

It is well known that unobserved heterogeneity can produce misleading estimates in survival analysis (see for example, Allison, 1995, p.233). The goal of this paper is to show how to estimate and apply a single event timing model with heterogeneity to real data with SAS. We consider three different models: An Exponential-gamma model, when individual-level time-to-event is exponentially distribu...

Department of Information Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, JAPAN (Received on February 27, 2012, revised on December 04, 2012) Abstract: The non-homogeneous Poisson processes (NHPPs) based software reliability models (SRMs) have gained much popularity in actual software testing phases to assess the software reliabil...

in order to restrain the potential of wind energy, the first step is to determine the wind energy potential. in this study the wind data was used from the three-hour frequency recording of 10-year period (2002-2011). to predict the occurrence probability of each wind speed, the two-parameter weibull function was used. the goodness of fit test by chi-square test showed that the wind speed distri...

The Weibull distribution is a flexible statistical model for describing multipath fading channels in both indoor and outdoor radio propagation environments. A new closed-form expression is derived for the moment generating function of the Weibull distribution, valid when its fading parameter assumes integer values. The performance of digital linear modulations operating on Weibull channels is s...