Fourth Hypothesis Analysis : Here, we test the research variables are tested concerning firm’s size as a control variable. Size as a control variable is defined as followings: firms having less than 760 billion Rials of assets (the Iranian monetary unit) are the small firms (27 firms),firms having between 760 and 6265 billion Rials of assets are the average firms (38 firms), firms having more than 760 billion Rials of assets in year 2015 are the large firms (26 firm)