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Confidence intervals for the difference between the coefficients of variation of Weibull distributions for analyzing wind speed dispersion

PeerJ. 2021 Jul 2:9:e11676. doi: 10.7717/peerj.11676. eCollection 2021.

Abstract

Wind energy is an important renewable energy source for generating electricity that has the potential to replace fossil fuels. Herein, we propose confidence intervals for the difference between the coefficients of variation of Weibull distributions constructed using the concepts of the generalized confidence interval (GCI), Bayesian methods, the method of variance estimates recovery (MOVER) based on Hendricks and Robey's confidence interval, a percentile bootstrap method, and a bootstrap method with standard errors. To analyze their performances, their coverage probabilities and expected lengths were evaluated via Monte Carlo simulation. The simulation results indicate that the coverage probabilities of GCI were greater than or sometimes close to the nominal confidence level. However, when the Weibull shape parameter was small, the Bayesian- highest posterior density interval was preferable. All of the proposed confidence intervals were applied to wind speed data measured at 90-meter wind energy potential stations at various regions in Thailand.

Keywords: Bayesian methods; Coefficients of variation; Dispersion; Generalized confidence interval; Gibbs algorithm; Markov chain Monte Carlo; Random walk Metropolis; The method of variance estimates recovery; Wind speed data.

Grants and funding

This research was funded by King Mongkut’s University of Technology North Bangkok. Contract no. KMUTNB-PHD-62-04 The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.