Journal Article bimodality 60E05 62Exx 62Fxx Bimodal distribution Bimodal model Bivariate unit-log-symmetric distribution Breast cancer data Class of distributions MCMC Weibull distribution beta distribution bivariate log-symmetric distribution bounded data estimation gamma generalized distribution inference maximum likelihood maximum likelihood estimation modelling partially linear regressions penalized maximum likelihood proportion data q-inference regression model soccer data stochastic representation trimodality unimodality