Better confidence intervals for the population coefficient of variation

The paper considers different confidence intervals for the population coefficient of variation based on the resampling methods, the ranked set sampling, the resampling methods for the ranked set samples and the partial ranked set sampling. We modify the existing confidence intervals for the population coefficient of variation using the trimmed mean in order to get better coverage accuracy. The results for the Gamma, Weibull, Log-normal and skew-normal distributions and for the real data set are reported. The best coverage probabilities are obtained using the confidence intervals based on the trimmed mean.