JIRSS is the official journal of the Iranian Statistical Society. This open-access peer-review journal provides an international forum for refereed original research work in Probability, Mathematical Statistics, and Statistical Methods. Prime importance is given to significant theoretical developments and to innovative applications of statistical methodology. Manuscripts submitted to the JIRSS must be in English and present original unpublished work and should not be under consideration for publication elsewhere. The JIRSS is published in one volume of two issues a year and appears in June and December. The journal follows the instruction of Committee on Publication Ethics (COPE).