When faced with the problem of comparing positively skewed outcome values, data transformations such as log and square root etc, are often used. However, this approach suffers with the difficulty in interpretability, lack of accuracy etc. That is, while the back transformation of mean is possible, but not for the standard deviation. This paper presents the analysis of comparing positively skewed outcome data by using generalized pivotal and log transformation approach for lognormally distributed data. Simulation experiment was conducted to examine the characteristics of generalized pivotal approach for small sample sizes and for large standard deviations. For the analysis of positively skewed biological data between two groups generalized p value and confidence interval approach for lognormal distribution is considered to be efficient as this provides direct statistical inference such as estimates, 95% CI and its p values.
