This paper differs from this prior work by Warren et al. in two different ways. First, we consider the parameter l to be a fixed constant, unlike having a probability distribution as in Bayesian approach. Second, in addition to providing the answer to the first question, we are interested in estimating the confidence interval of the ratio of two concentrations which is new work. For difference between credible interval and confidence interval, see [13] . Both approaches give good results depending upon the question one is trying to answer.