5 citations · 8 across the 10 of their papers we have counts for
17 papers
Bivariate log-symmetric models: distributional properties, parameter estimation and an application to fatigue data analysis
Roberto Vila, Narayanaswamy Balakrishnan, Helton Saulo +1
The bivariate Gaussian distribution has been a key model for many developments in statistics. However, many real-world phenomena generate data that follow asymmetric distributions,…
Unit-log-symmetric models: Characterization, statistical properties and its use in analyzing internet access data
Roberto Vila, Narayanaswamy Balakrishnan, Helton Saulo +1
We present here a unit-log-symmetric model based on the bivariate log-symmetric distribution. It is a flexible family of distributions over the interval . We then discuss i…
Theoretical results and modeling under the discrete Birnbaum-Saunders distribution
Filidor Vilca, Roberto Vila, Helton Saulo +2
In this paper, we discuss some theoretical results and properties of a discrete version of the Birnbaum-Saunders distribution. We present a proof of the unimodality of this model.…
A parametric quantile beta regression for modeling case fatality rates of COVID-19
Marcelo Bourguignon, Diego I. Gallardo, Helton Saulo
Motivated by the case fatality rate (CFR) of COVID-19, in this paper, we develop a fully parametric quantile regression model based on the generalized three-parameter beta (GB3) di…
On a quantile autoregressive conditional duration model applied to high-frequency financial data
Helton Saulo, Narayanaswamy Balakrishnan, Roberto Vila
Autoregressive conditional duration (ACD) models are primarily used to deal with data arising from times between two successive events. These models are usually specified in terms…
On some properties of the bimodal normal distribution and its bivariate version
Roberto Vila, Helton Saulo, Jamer Roldan
In this work, we derive some novel properties of the bimodal normal distribution. Some of its mathematical properties are examined. We provide a formal proof for the bimodality and…